Here I would like to return to an old topic with a fresh approach, partly inspired by 'Nobody,' a regular contributor to this site.
As early as August 10th 1969 Professor D.C.B. Marsh of the American Cryptogram Association (ACA) was commenting on the Zodiac ciphers. In the San Francisco Sunday Examiner & Chronicle he praised Donald Harden's deciphering skills and called the code "complicated and obviously drawn by somebody who knows his business". 
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The Zodiac Killer had already responded to prompts by Vallejo Police Chief Jack Stiltz to send more details to prove the letter writer and killer were one and the same. The more the Zodiac Killer wrote, not only lessened his time for killing, but may have provided additional clues to detectives regarding his identity. This tactic was likely adopted by Professor D.C.B. Marsh in the October 22nd 1969 San Francisco Examiner newspaper article by Will Stevens, which laid down a challenge to the Zodiac Killer to reveal his name. The newspaper stated "Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name -in cipher code - would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name." 

Clearly, Dr. Marsh and the detectives would have considered it highly unlikely for the Zodiac Killer to respond by giving us his name, but while he was constructing ciphers he wasn't murdering innocent civilians. There also remained an outside chance that Zodiac would rise to the challenge and create a code, "however complicated", that Dr Marsh and his fellow cryptographers could unpick. This article, rather than a straightforward challenge to Zodiac, could have been deliberately manufactured with the assistance of detectives, to bait the Zodiac Killer into using a particular methodology in his cipher construction. If the police knew the source of Zodiac's inspiration, then it could unearth the cipher technique he employed when designing his next code. 

'Nobody' considered the idea that the Zodiac Killer may have used a foreign language in the cipher, or possibly a rotating key that switches at certain intervals. By employing such a technique, the Zodiac Killer could make the cipher virtually "crackproof". 
The article in the October 22nd 1969 San Francisco Examiner may have been specifically designed to lead the Zodiac Killer down a particular path, making his next cipher easier to crack. Dropping innocuous sections of text into an article such as "to quote Edgar Allen Poe, that any cipher created by man can be solved by man", can be specifically designed to guide the Bay Area murderer into using one of Edgar Allan Poe's cipher techniques or a model suggested by him. We know the Zodiac Killer was an avid reader of the newspapers and may have took this bait of using a publication by Edgar Allan Poe, thinking he was getting one over on Dr Marsh and the police. The hope from the standpoint of law enforcement, was that the Zodiac Killer would bite the hook and get reeled in. 

Sixteen days later the Zodiac Killer mailed the 340 cipher revealing, not his name, but his identity, carefully positioned at the base of his cipher. This catapulted the idea that the Zodiac Killer had indeed responded to the article by Dr Marsh, but wasn't quite ready to reveal his name to authorities. But it is my belief that the Zodiac Killer did create the 340 and 13 Symbol ciphers in tandem, with a view to inextricably link his identity to his name using the word "Zodiac" on the final row of the 340 cipher, with the three 8's as the conduit between the two. See here.

The Zodiac Killer, however, would hold back his '13 Symbol' cipher for approximately six months. Zodiac researcher Michael Cole stated "Clearly, the Zodiac did not send the cryptogram to Marsh, as had been requested (this non-public way of satisfying the challenge was apparently unacceptable to the attention-craving serial killer). Neither did he respond in a time frame that most would have expected. But these details matter little. In fact, the timing itself provides yet another reason to conclude that what we have here is a specific instance of cause and effect. As mentioned, this article was published in the Examiner on October 22, 1969.  Six months to the day later, April 22, 1970, the people of the San Francisco Bay Area were reading about the My Name Is cipher in the Chronicle."

But there may have been a much more cunning reason why the Zodiac Killer delayed his mailing of the April 20th 1970 communication, and it has everything to do with Edgar Allan Poe. Did the Zodiac Killer pick up on the wording of Dr. D.C.B. Marsh in the article, create and mail his '13 Symbol' cipher based on something in the writings of Edgar Allen Poe? 

We can see in the Edgar Allan Poe essay 'A Few Words on Secret Writing,' at the very beginning he shows the alphabet being split into two halves of 13 letters, A to M, and N to Z.
"Were two individuals, totally unpractised in cryptography, desirous of holding by letter a correspondence which should be unintelligible to all but themselves, it is most probable that they would at once think of a peculiar alphabet, to which each should have a key. At first it would, perhaps, be arranged that a should stand for z, b for y, c for x, d for w, &c. &c.; that is to say, the order of the letters would be reversed. Upon second thoughts, this arrangement appearing too obvious, a more complex mode would be adopted. The first thirteen letters might be written beneath the last thirteen, thus:
n o p q r s t u v w x y z
a b c d e f g h i j k I m; and, so placed, a might stand for n and n for a, o for b and b for a, &c. &c. This, again, having an air of regularity which might be fathomed, the key alphabet might be constructed absolutely at random." ​​

The Zodiac Killer not only created the April 20th 1970 cipher with 13 characters, but it too began with an A and ended with an M, just like the suggested encryption technique featured by Edgar Allan Poe. Notice the way the cipher is organized symmetrically using the alphabetical characters, the three 8's and the two symbols. The same symmetry was observed when placing half the alphabet alongside the 13 character cipher. See here.  

The Dr. Marsh newspaper article opened with "A Challenge perhaps unique in the annals of American crime was injected today into the bizarre case of the killer who begins his letters to newspapers 'This is the Zodiac Speaking'."
The article continued, and bemoaned the fact that Zodiac hadn't revealed his true identity: "Zodiac has not done this, because to tell the complete truth in relation to his name - in cipher code - would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code - however complicated - which will truly and honestly include his name." 

'A Few Words on Secret Writing' stated "This challenge has elicited but a single response, which is embraced in the following letter. The only quarrel we have with the epistle, is that its writer has declined giving us his name in full. We beg that he will take an early opportunity of doing this, and thus relieve us of the chance of that suspicion which was attached to the cryptography of the weekly journal above-mentioned–the suspicion of inditing ciphers to ourselves. The postmark of the letter is Stonington, Conn." ​link. 

If the Zodiac Killer was basing the '13 Symbol' cipher on the Dr. Marsh article and secret writing of Edgar Allan Poe, why did he wait approximately six months to mail it to the San Francisco Chronicle?
It may not have been the six month anniversary that was important to him, but the only date mentioned in the Edgar Allan Poe literature, 'A Few Words on Secret Writing'. The date was April 21st. 
Had the Zodiac Killer deliberately waited six months to ensure his '13 Symbol' cipher letter would be postmarked April 21st, or be published on April 21st, which unfortunately for him never materialized? He was slightly early on the mailing, resulting in the postmark of April 20th, and the San Francisco Chronicle published his cipher in the April 22nd edition, effectively thwarting any intentions to recreate the Connecticut letter.

However, the possibility remains, that the Zodiac Killer could have used one of the cipher techniques employed or suggested by Edgar Allan Poe in 'A Few Words on Secret Writing', and the idea proposed by 'Nobody' regarding the use of a second language as the key, a much more viable proposition than initially considered.
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 "It is not to be supposed that Cryptography, as a serious thing, as the means of imparting important information, has gone out of use at the present day. It is still commonly practised in diplomacy; and there are individuals, even now, holding office in the eye of various foreign governments, whose real business is that of deciphering. We have already said that a peculiar mental action is called into play in the solution of cryptographical problems, at least in those of the higher order. Good cryptographists are rare indeed; and thus their services, although seldom required, are necessarily well requited. An instance of the modern employment cipher is mentioned in a work lately published by Messieurs Lea & Blanchard, of this city–“Sketches of Conspicuous Living Characters of France.” In a notice of Berryer, it is said that a letter being addressed by the Duchess de Berri to the legitimists of Paris, to inform them of her arrival, it was accompanied by a long note in cipher, the key of which she had forgotten to give. “The penetrating mind of Berrver,” says the biographer, “soon discovered it. It was this phrase substituted for the twenty-four letters of the alphabet–Le,gouvernement provisoire.” 'A Few Words on Secret Writing' by Edgar Allan Poe.

In a recent article David Oranchak posed the question "Are the Ciphers Gibberish", analyzing the pros and cons to the legitimacy of the Zodiac 340 cipher. There is, however, another legitimate argument to be discussed when searching for a solution to the Zodiac Killer's second cipher. Is it worth trying to solve at all? If it does contain a message, it will likely be a collection of inane ramblings akin to the solved 408 cipher. There will of course be the immense notoriety attached to your name, having been the cryptographer who broke the infamous Zodiac code, from which numerous television appearances and a book deal will inevitably follow. In the midst of tragedy, your name will be up in lights. But here is the reality check. Even if you do achieve the seemingly insurmountable task of unequivocally solving the 340 cipher, then comes the next insurmountable hurdle - convincing people you have the correct solution. In a Zodiac community wearily grazing on skepticism and fueled by a heavy dose of déjà vu syndrome, your perfectly good solution will likely drift on down the river with barely a ripple from the esteemed adjudicators.   

Even if it does get snagged by an overhanging branch for a fleeting moment, attempting to prove that the "key" used to decipher it, is the one Zodiac intended, will again create a hill you can never climb.

There are so many claimed solutions to the 340 cipher haystack, that if one really existed, it will eventually be as hard to find as a solution to the cipher itself. David Oranchak stated here:   
​"The 340 cipher has 63 unique symbols. If one of 26 plaintext letters can be assigned to each symbol, then the number of possible solutions is 26 raised to the 63rd power. So, how many of those solutions would computers need to examine PER SECOND to finish within 100 years? The answer is about 4.4 x 10^80 solutions, or 440 million billion billion billion billion billion billion billion billion. This is LIGHT YEARS beyond what current computers are capable of.
According to Top500.org, the world's fastest supercomputer as of November, 2011, achieved a computational power of 10.51 Petaflop/s, or 10.51 quadrillion floating point operations per second. If you were somehow able to check a decryption solution of the 340 cipher using a single floating point operation, then this supercomputer could go through all of the possible solutions to the 340 cipher in about 1.3×10^57 years. By comparison, our humble universe is estimated to be only 13.7 x 10^9 years old!"

With so many variables that can be applied to the cipher, or more importantly, the one conjured up by the warped and dissociative brain of Zodiac, the probability is, that a supercomputer designed by logic and born from reality will probably be heading course on the wrong superhighway. Throw in a handful of Zodiac errors into the mix, could mean proving your solution an impossible task to the baying hordes of furrowed experts, armed with statistical probabilities. Solving the 340 cipher may yet prove to be the easy part, however, convincing somebody else you have, could take a quadrillion years you haven't got.

David Oranchak stated "When Z408 was cracked, the papers talked about how the solvers took advantage of patterns found in the cipher text. Zodiac could have focused on somehow removing those patterns from Z340. Or maybe he found some obscure idea in a book or one of those pulp fiction detective stories".
​Herein lies part of the problem. If you discover an obscure idea that answers key elements of the 340 cipher, or provides a readable message (possibly using a rotating key code), then it could be argued that your obscure idea is so obscure, that it isn't worth considering as a credible solution and thereby roundly dismissed as lunacy. The more crazy the solution, the more unlikely it is, despite being crafted by the perfectly sane Zodiac.

Alternatively, how do you prove the cipher gibberish while it still remains unsolved in the eyes of most observers. By extension, if it's unsolved, then it still has a possible solution. But be warned - if you do find the real solution to the 340 cipher, you will have to work far harder than the Harden's did in 1969 to convince the world you are correct. And my guess is, you never will.    

In the last three articles it was proposed that the author of the 408 cipher may have left his identity within the final 18 characters. He specifically told us that he would not give us his name, but assured us his identity was concealed within the cipher - reasoned to be something like "I am the Zodiac Killer." The theme of his identity and name were integral to the final third of the cipher and letter mailed to the San Francisco Chronicle on July 31st 1969, and may very well have manifested through both his second and third ciphers as well. The third cipher began with "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...."- therefore, the final line of the second cipher (340 cipher) may be the 'narrative bridge' between the first and third cryptic offerings. 

The first cipher achieved everything the Zodiac Killer had wished for. He had fashioned using threats and newspaper rivalry maximum exposure for his handiwork, which was very quickly published by the Vallejo Times-Herald, San Francisco Examiner and San Francisco Chronicle. The failure of Zodiac to give us his name did not satiate the desire of some in the quest for the real identity of the killer, and was championed by Dr D.C.B. Marsh, president of the American Cryptogram Association, who on October 22nd 1969 in an article published by the San Francisco Examiner, stated "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in a cipher to established cryptogram experts. "Zodiac" had not done this, Marsh suggested, because to tell the complete truth in relation to his name, in cipher code, would lead to his capture. I invite 'Zodiac' to send The American Cryptogram Association a cipher code-however complicated."

​This article was not to go unnoticed by the killer, who, two and a half weeks later mailed his infamous 340 cipher, unsolved to this day according to official sources. This cipher was to become the all-important bridge between cipher one and three. If he gave us his identity (the Zodiac Killer) in the unsolved 18 characters of cipher one, and stated "my name is" in cipher three (supposedly giving us his name), then by logical extension, cipher two should have been the promise of a name, and the conduit between the two.

If we can provide a compelling reason to show that the near-Zodiac on the final line of the 340 cipher was actually intended to be deciphered to 'Zodiac', then we are left with the final two characters of the cipher to decode, thereby bridging the gap between cipher two and three. 
Using the most powerful supercomputers in the world and the talent of some of the brightest minds in cryptography, the 340 cipher has failed to buckle. So, it's time to use the character of the Zodiac against himself, and his willingness to respond to the newspapers.

If the Zodiac Killer is responding to Dr D.C.B. Marsh, then he clearly isn't prepared to give us his name immediately in the November 8th 1969 '340 cipher', as the opening line in his April 20th 1970 communication would testify to. It would be over five months later that he stated "my name is".  Therefore, the final two characters of the 340 cipher are the conclusion to an open-ended promise of something more to come, in similar fashion to "my name is."  The Zodiac Killer certainly wasn't going to miss the opportunity to keep Dr D.C.B. Marsh and the public waiting just a little bit longer. 
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The final line or sequence of the 340 cipher probably read "The next cipher will reveal who the Zodiac is" or "I will soon reveal who the Zodiac is" - or something along these lines. This 'promise' can be seen in his opening gambit of the April 20th 1970 communication: "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...." ​
The statement of "by the way have you cracked the last cipher I sent you" is superfluous, as he knows only too well the 340 cipher has not been cracked, yet, it also lacks his usual abrasive sarcasm. However, it is followed by "my name is", and therefore could be construed as the conclusion to his promise from the final line of his 340 cipher and to Dr D.C.B. Marsh, and the allegorical  bridge between the two ciphers.

But how do we know that the near-Zodiac on the final line of the 340 cipher was to be decoded to 'Zodiac'?  Because he fashioned a bridge between cipher two and three using his pseudonym. Placing the real spelling of Zodiac under the '340 cipher' version of Zodiac, and counting the alphabetical difference numerically between the columns (see here), we achieve the numbers 000888. When combined, the three circled 8's found on the '13 Symbol' cipher.
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These six characters of the 340 cipher were effectively carried forward numerically and placed front and center of the '13 Symbol' cipher design. You will also notice that the two characters either side of three 8's (shown on the right), are both visible either side of the near-Zodiac on the 340 cipher. A total of eight characters and three circled 8's the common link or bridge between cipher two and three - in which the name of Zodiac played a pivotal part in the formation of the 'My Name is Cipher'. The story is now complete. 

The Zodiac Killer stated on July 31st 1969 "I will not give you my name, but in this cipher is my identity." He promised in the 340 cipher, in a response to Dr D.C.B. Marsh, that he would soon reveal his name. Then, five and a half months later, on April 20th 1970 he stated "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...." 

Do ciphers two and three really contain a full and coherent message, not dissimilar to the 408 cipher solution, or had the Zodiac Killer taken Dr D.C.B. Marsh's advice "to send The American Cryptogram Association a cipher code - however complicated", and taken it a step too far?

It seemed rather fortunate that the 'Halloween' card mailed on October 27th 1970, if designed totally independently to the 340 cipher, that Paradice and Slaves could be found perfectly bisecting the 340 cipher, 17 by 17 characters. Not to mention the word "By" being found in all four quadrants. This is discussed in more detail in the article 'The Illusion of the 340 Cipher.'  
The 'Halloween' card was almost certainly highlighting the Lake Berryessa attack on Bryan Hartnell and Cecelia Shepard, tied up with rope (plastic clothesline) and brutally stabbed sixteen times by the Zodiac Killer. The phrase "peek-a-boo you are doomed" referencing the children's game peekaboo, where 'hiding behind that tree' is sometimes added. This would also be the second time "by knife" would be used - linking the 'Halloween' card to the Volkswagen Karmann Ghia of Bryan Hartnell.
Since these two 'methods of death' (rope and knife) were instrumental to the attack on the young couple, we will focus on Paradice, Slaves, By Knife and By Rope. 
On the 'Halloween' card it is apparent that "By" is written vertically for "knife" rather than horizontally, as displayed by the other 'methods of death'. Could this be a sinister inference to a knife being driven downwards and the predominant focus of this card?   

If we color in the five characters underneath the 'Y' in the bottom left quadrant of the cipher, as is portrayed on the 'Halloween' card, it can be seen that the 'right facing V' would represent the 'E' of knife.
If we  color in the four characters underneath the 'B' in the bottom right quadrant of the cipher, as is portrayed on the 'Halloween' card, it can be seen that the 'right facing V' would represent the 'E' of rope.
To complete the word Paradice and Slaves a 'left facing V' had to be found in the last section of both words for parity. In this instance a 'left facing V' represented the letter 'E'.
When the Zodiac Killer introduced his 408 cipher in the July 31st letters, he stated "Here is part of a cipher" or "Here is a cyipher." When challenged to design another cipher by D.C.B. Marsh in the San Francisco Examiner on October 22nd 1969, the 340 cipher arrived just over two weeks later. The article was entitled 'Cipher Expert Dares Zodiac to Tell Name'. Bearing in mind that the 340 cipher began with "Her," could it have started with "Here is a cipher" or "Here's a cipher" (to marry with the 'P' of Paradice) in direct response to cryptographic expert D.C.B. Marsh.
There are 10 'left or right facing' V's in the entire 340 cipher. If the latter hypothesis was correct, then at least 50% of these would be represented by the letter E, in respect of Here, Paradice, Slaves, Rope and Knife.  

There is no definitive evidence to totally negate the idea that the 340 cipher contains a viable solution- with the mystery and allure of the Zodiac Killer code the driving force behind people wishing it were genuine. This, of course, exempts the 500+ people who have already solved the 340 cipher, in solutions now extending longer than the Bayeux Tapestry.  
Obviously, Zodiac researchers who specialize in the ciphers rather than the crimes themselves, have a vested interest in wishing the cipher to be a hidden message. This is the belief that keeps the dream alive.
But did the Zodiac Killer really have the ability to create a more difficult cipher than the 408, with a reasonable expectation of a solution. Placing 29 unique characters into a 32 symbol cipher, and creating a 13 symbol code would suggest not.
The October 22nd 1969 Examiner newspaper article by Will Stevens, laid down a challenge to the Zodiac Killer from the president of the American Cryptogram Association (ACA), Professor D.C.B. Marsh, to reveal his name. This may be the article that inspired the 340 cipher, and by association, the 'Halloween' card mailed approximately one year later.
 "Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name-in cipher code-would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code, which will truly and honestly include his name."
This contention is probably true- that the Zodiac Killer wouldn't reveal his name in any cipher (other than his pseudonym), and additionally, he likely used the fact "that any cipher created by man can be solved by man" as a springboard to create something extra special, other than a cipher. If we contend that the Zodiac Killer wrote his final letters in 1974, then is it likely that a killer touted as an attention seeker, could resist dropping us clues to the 340 cipher in his subsequent letters, spanning in excess of four years. 
Each and every one of his final three communications in late 1970 and early 1971 effectively told us he was crackproof. The upside down text on the October 5th 1970 'Pace' card stated "Fk I'm crackproof." The October 27th 1970 'Halloween' card proclaimed "sorry no cipher." The March 13th 1971 'Los Angeles' letter boasted "Like I have allways said, I am crack proof." But the Zodiac Killer hadn't always said he was crackproof- only in the two communications either side of the 'Halloween' card announcing "sorry no cipher." The suggestion he was crackproof, thereby not arising from his perceived ability to evade police, but from his smugness in knowing he created three ciphers he knew would never be solved. 

The Tim Holt comic find by Tahoe27 in 2013, and the recent assertion of a close alliance, not only with the 'Halloween' card, but the 340 cipher, has been covered here to reject the 340 cipher as containing a viable and coherent message.
In view of the "by knife" attribution on Bryan Hartnell's car door, it is arguable that the Zodiac Killer had the Tim Holt comic book or Rota Fortunae (Wheel of Death) in mind as he wrote on the car door. In other words, the concept predated the September 27th 1969 Lake Berryessa stabbings, rather than just the 'Halloween' card. The Lake Berryessa "by knife" attribution becoming the part inspiration for the complex puzzle of the 340 cipher.
The "by knife" method of death (on the right) is clearly the only one falling within its quadrant, as opposed to the others, which are all connecting with the central column.
This method of death was certainly prioritized by the Zodiac Killer, having placed it on Bryan Hartnell's vehicle (despite the fact the crime was obviously committed with a knife). The feasible presence of "by knife" within the 340 cipher. The possibility of a crude 'Halloween' card design in the December 16th 1969 'Fairfield' letter featuring "death by knife," along with the "Bleeding Knife of Zodiac" drawing. And finally, the 'October 27th 1970 'Halloween' card design and comic book, both containing "by knife" and mirroring the 340 cipher and 'Fairfield' letter.
Below are the speculative beginnings, attempting to interweave the '13 Hole' postcard into the emerging design. 

This is the last time this subject will be tackled for the foreseeable future, unless something magical sticks its head above the parapet- but before that happens- there is just one more addition to the idea of an extremely close alliance between the 'Halloween' card and 340 cipher, and the suggestion that the 340 cipher is not a meaningful and coherent message by the Zodiac Killer.
Just about every feature of the October 27th 1970 'Halloween' card, including the envelope and stamp, can be shown to exist within the 340 cipher, making the December 2013 discovery by Tahoe27, of a Tim Holt comic book connection, all the more compelling. Her discovery may have opened the door to finally end the debate on the validity of the 340 masterpiece, and place the pseudonym 'Zodiac' front and center to the 'Death Wheel' featured on the comic book cover.
At what juncture the Zodiac first stumbled across his pseudonym is of little importance, however, it could be argued that when he found it, he would likely research the name 'Zodiac' and use elements of his research to incorporate into his future correspondence. If he had happened upon the Tim Holt 'Death Wheel' comic prior to November 8th 1969, then the light bulb may have switched on, and his design of a crackproof cipher began in earnest. And possibly, a 340 cipher designed in tandem with the Tim Holt comic and cipher three, which he mailed just over five months later on April 20th 1970. His opening line of "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is....", he may have already known the answer to when he manufactured the illusion of a 340 character message.        

Here is a brief recap before we move on.
The 'Halloween' card stamp contained 17 letters "In the beginning God" that slotted nicely onto the first line of the 340 cipher, with characters 15,16 and 17 awkwardly similar- including the half-earth image present on the stamp.
Paradice and Slaves can be shown as a distinct possibility, bisecting the 340 cipher horizontally and vertically, just like the 'Halloween' card arrangement. Seventeen characters horizontally and vertically in either direction, to create the perfect crosshairs of Zodiac.
The word "by" can be found in all four quadrants of the 340 cipher, mirroring the 'Halloween' card arrangement.
At least seven, possibly eight characters on the 14th line of the 340 cipher can be formed into the design of the 'Halloween' card inner. Explanation here. 
"Sorry no cipher" written on the envelope inner and designed in similar fashion to Paradice and Slaves arrangement on both the 'Halloween' card and 340 cipher, explicitly instructed us that no cipher existed on November 8th 1969.
One has to presume that all these fell here by accident (including the inference to Zodiac on the 20th line), because to believe otherwise, would pour huge doubt on a Zodiac Killer who was able to simultaneously create a uniform message within the 340 cipher in conjunction with a 'bag of puzzles'. 
However, the Tim Holt 'Death Wheel' comic is not only interesting because it contains By Fire, By Gun, By Rope and By Knife, found in the 'Halloween' card, or because of "Redmask" or "Lady Doom," but because of the origin of the 'Death Wheel' or 'Wheel of Fortune' itself. 
Had the Zodiac Killer read anything about the pseudonym 'Zodiac' when he first appropriated it, then he may have known the relevance of the 'Wheel of Fortune' or 'Rota Fortunae,'. thereby triggering the inspiration for the 340 cipher, and the eventual 'Halloween' card explanation or solution to his devilish trick and treat.          

We could just assume that when the Zodiac Killer spotted the Tim Holt 'Death Wheel' comic book, he liked the fact it represented some or all of his killing methods, and simply chose it because of its menacing touch. However, he may have chosen it because of the pseudonym he had grown so attached to- a pseudonym he would seemingly place at the foot of the 340 cipher.
The 'Wheel of Fortune' or 'Rota Fortunae' has a long and rich history, crossing many cultures and eras. Here is an excerpt from Wikipedia:
"In medieval and ancient philosophy the Wheel of Fortune, or Rota Fortunae, is a symbol of the capricious nature of Fate. The wheel belongs to the goddess Fortuna (Greek equivalent Tyche) who spins it at random, changing the positions of those on the wheel: some suffer great misfortune, others gain windfalls. Fortune appears on all paintings as a woman, sometimes blindfolded, "puppeteering" a wheel."
The great windfall may be the promise of paradise, but the downside is the servile nature expected by the one who summoned you.
But here is the interesting part- again taken from Wikipedia. 
"The origin of the word is from the "wheel of fortune" - the zodiac, referring to the Celestial spheres of which the 8th holds the stars, and the 9th is where the signs of the zodiac are placed. The concept was first invented in Babylon and later developed by the ancient Greeks. The concept somewhat resembles the Bhavacakra, or Wheel of Becoming, depicted throughout Ancient Indian art and literature, except that the earliest conceptions in the Roman and Greek world involve not a two-dimensional wheel but a three-dimensional sphere, a metaphor for the world. It was widely used in the Ptolemaic perception of the universe as the zodiac being a wheel with its "signs" constantly turning throughout the year and having effect on the world's fate (or fortune)." link.
The zodiac is an area of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The paths of the Moon and visible planets are also within the belt of the zodiac. The Zodiac is divided into 12 signs beginning with Aries and Taurus.
The Zodiac wheels have multiple cultural adaptations, shown here in a Wordpress blog:
"These zodiac/time wheels are not common in Eastern Orthodox iconography, but they are found in one variation or another occasionally — usually, as here — in the form of wall paintings in churches. When seeing such a “Wheel of Time” — also called a Wheel of Life — one cannot help thinking of those Tibetan images that also represent a wheel of life as the “Wheel of Becoming” — in this case a wheel of rebirth:"
Here is one final extract from the book 'Deep Value:
Plutarch says that Servius knew "fortune is of great moment, or rather, she is everything in human affairs" because it was through good fortune that he had ascended from slave to king. In Roman mythology Fortuna was the goddess of fate, and the personification of chance. She turned the Rota Fortunae- the Wheel of Fortune- which dictated the destiny of man." Therefore, did Zodiac dictate the destiny of his victims-  By Fire, By Gun, By Rope and By Knife- the very reason the 'Wheel of Death' portrayed on the Tim Holt comic was so very appealing.

The discovery by Tahoe27 linking the Tim Holt comic was fascinating in so many ways, yet, it may not have been the inspiration behind the 'Halloween' card, but the inspiration behind the 340 cipher and its accompaniment- the '13 Symbol' cipher.
If the Zodiac Killer had done his research and discovered the 'Wheel of Fortune' or 'Rota Fortunae', and its connection to the word 'Zodiac', then the Tim Holt comic may have been a gift from heaven- an offering he just couldn't resist. 
Five weeks after the November 8th 1969 340 cipher, the December 16th 1969 'Fairfield' letter may have shown the early machinations of the Zodiac design, appearing in rudimentary code- the full explanation of which would have to wait until October 27th 1970..
The interconnectivity between the 'Halloween' card, Tim Holt 'Death Wheel' comic, the pseudonym 'Zodiac' and the 340 cipher is an intriguing and perplexing blend of mystery. One that came together by deliberate intent, or came together from the mind of somebody wishing it were true.

There are many ways to interpret the 'Dripping Pen' card mailed by the Zodiac Killer on November 8th 1969 and here is another.
​Some people use the 'evidence of absence' argument to suggest the Lake Berryessa attacker was not the Zodiac Killer- articulating that his lack of mailed correspondence after the double stabbing was evidence for his absence from the crime scene.
​His communication on the car door just six minutes after the attack- probably to him- seemed like unassailable proof he was placing himself at the crime scene, just like attaching Paul Stine's shirt piece to his October 13th 1969 letter.
​At Lake Berryessa he took his handwriting to the crime scene, while at Presidio Heights he took the crime scene to his handwriting. A reverse signature one might say. However, not many people question Zodiac's involvement in the murder of taxicab driver Paul Stine. The idea that the Zodiac Killer never communicated his involvement in the Lake Berryessa crime is patently false, despite our need for a more comprehensive attribution to the events of September 27th 1969. Yet, his correspondences on October 13th 1969 and November 8th 1969 may very well have both referenced the Lake Berryessa attack, but in different ways.
The author of the October 13th 1969 Paul Stine letter opened with the words "This is the Zodiac speaking. I am the murderer of the taxi driver over by Washington St + Maple St last night, to prove this here is a blood stained piece of his shirt. I am the same man who did in the people in the north bay area."
The Zodiac Killer on the car door of Bryan Hartnell's white Karmann Ghia clearly attributes both of his first two attacks under the banner of Vallejo, despite the fact David Faraday and Betty Lou Jensen were murdered in Benicia. In fact, the Zodiac Killer never referenced Benicia in any of his communications, while he mentioned Vallejo several times. If the Zodiac Killer played no part in the Lake Berryessa attack, then his above introduction could have read "This is the Zodiac speaking. I am the murderer of the taxi driver over by Washington St + Maple St last night, to prove this here is a blood stained piece of his shirt. I am the same man who did in the people in the Vallejo area." However, he chose to use the "north bay area" for the first time, which incorporates the Napa and Sanoma wine regions. ​

Despite the claims that an impostor could have faked the Lake Berryessa phone call to mimic Zodiac's rhetoric of the Blue Rock Springs call, by reading the transcripts widely publicized in the newspapers, it appears the copycat would then fail to read the newspapers of the Benicia attack, and bundled both attacks under the banner of Vallejo on the car door, in complete harmony with a Zodiac Killer who always failed to document the simplest of facts- that his first crime was perpetrated in Benicia. The implication being- that they are one and the same person.
The divergence from Vallejo in the October 13th 1969 Stine letter confession, therefore, proof of his admission to the Lake Berryessa attack. The Zodiac Killer would then further indicate his involvement by the lake, in the cryptic November 8th 1969 'Dripping Pen' card communication, not only by the addition of "Sept"  in his running victim count, but through the cover image and wording within it.  
The style of the card may have been purposely chosen in reference to the Lake Berryessa attack and mailed in unison with the 'Bus Bomb' letter, which  elaborated upon his recent murder.
On October 18th 1969, Attorney General Thomas C Lynch implored Zodiac to turn himself in, stating "We will see that he gets help and all his rights are protected. He is obviously an intelligent individual. He knows that eventually he will be taken into custody, so it would be best that he give himself up, before tragedy is written in blood." 
Three weeks later the Zodiac Killer mailed a greeting card, depicting a fountain pen having been washed by its owner. The card itself read "Sorry I haven't written, but I just washed my pen...and I can't do a thing with it." Zodiac then added the words "This is the Zodiac speaking. I though you would nead a good laugh before you hear the bad news. You won't get the news for a while yet. Could you print this new cipher in your frunt page? I get aufully lonely when I am ignored, so lonely I could do my Thing."

It is clear the Zodiac has simply parroted the word "thing" from the wording on the card, and began to write the letter 'T' in lower case. It is equally probable the Zodiac wrote the entire word "thing" in normal writing, before emphasizing it in bold fashion, to highlight its importance. 
​The phrase "and I can't do a thing with it" is referring to a pen that now cannot be used, having been damaged by water. This is often taken as a pen accidentally left in clothing and washed, however, it may have a more sinister implication. 
The threat of "I could do my Thing," is obviously referencing murder- but by parroting the word "thing" from the card, which is explicitly referencing the pen, the Zodiac Killer may be associating the pen with murder. More specifically, the murder of Cecelia Shepard.  
The Zodiac Killer's dominant hand would certainly have been covered in blood after the Lake Berryessa double stabbing, so any pen subsequently used to write on the car door would equally have been smothered in blood, thereby making the November 8th 1969 'Dripping Pen' card, of a washed pen, not an unusual choice by the killer. The killer may have worn gloves and removed them before writing on the car door, but the implication of the card remains. 
The six exclamation marks after the word "Thing" are as notable, as they are excessively repetitive. The Zodiac Killer has also deliberately or accidentally underlined the word "Thing" exactly six times. These two characteristics may be purely unintentional on behalf of the author, but considering the Zodiac Killer is claiming 7 victims at this juncture, it would be remiss not to mention that the Lake Berryessa murder of Cecelia Shepard would have been the Zodiac Killer's sixth victim.
One theory behind the origin of the exclamation mark, is that it is derived from a Latin exclamation of joy, which may not have been lost on a killer bereft of empathy. 

This is a continuation of the article 'The Illusion of the 340 Cipher,' attempting to show Zodiac's second code was nothing more than a collection of puzzles, interconnected to his other mailed correspondences.   
The 'Halloween' card mailed by Zodiac on October 27th 1970 predominantly featured within the 340 cipher, in that, Paradice and Slaves was able to be shown bisecting the cipher horizontally and vertically across its mid-section, along with 'by' being found in all four quadrants. The text of the stamp 'In the Beginning God' fitted nicely on the first line of the cipher, with the word 'God' aligning nicely with characters 15, 16 and 17. In addition, the half-earth image on the stamp mirrored exactly with character 16.
The idea that all these connections to the 'Halloween' card, '13 Symbol' cipher and 'Exorcist' letter could be forged within the 340 cipher by chance, was presented as so unlikely, they must have been created by design.
The darkened section of the 'Halloween' card inner reads like an instruction manual. The skeleton's finger of 4-TEEN directing us downwards 14 lines, to find the word 'BOO.'
The 14th line containing four shaded circles, three of which can be formed into the word BOO, complete with exclamation mark (I + black circle).
The next feature on the 'Halloween' card is the strange symbol.  
​  

The following two characters on the 14th line of the 340 cipher can easily be rearranged, by reversing the letter F and attaching its adjacent character, to mimic the strange symbol on the 'Halloween' card. 
​The next feature on both the 14th line and 'Halloween' card is the letter N and the letter Z. Rotating the N ninety degrees clockwise forms the completed sequence of BOO!, strange symbol and letter Z on the 340 cipher.
This is achieved using 8 characters on the 340 cipher, all in close proximity to each other. Just like 'In the Beginning God' and 'Paradice and Slaves,' is this another stroke of luck, or has this been deliberately fashioned by the Zodiac Killer as part of a game. 
It is further apparent that the word 'BOO' (in reverse) bisects the word 'Paradice' running vertically down the cipher, separating the letters I and C.
On the 'Halloween' card in this approximate area, the Zodiac Killer has mirrored the letter N, which may or may not hold some significance.
This could be a case of simply looking for patterns and finding them, but with so many having now been unearthed, is this compounding evidence to reliably dismiss the 340 cipher as harboring a coherent and uniform message, as demonstrated by the 408?
The Zodiac Killer may have dropped several clues in his later communications, resisting the temptation of giving us the final solution:
"But, then why spoil the game."    

It would be befitting that the Zodiac Killer's last correspondence may possibly be the 'Eureka' card mailed in the December of 1990, considering the last major work of Edgar Allan Poe was the non-fiction offering Eureka: A Prose Poem.    
"Adapted from a lecture he had presented, Eureka describes Poe's intuitive conception of the nature of the universe with no antecedent scientific work done to reach his conclusions. He also discusses man's relationship with God, whom he compares to an author. Similar to his theories on a good short story, Poe believes the universe is a self-contained, closed system. In coming to his conclusions, Poe uses ratiocination as a literary device, through his character C. Auguste Dupin, as if Poe himself were a detective solving the mystery of the universe. Eureka, then, is the culmination of Poe's interest in capturing truth through language, an extension of his interest in cryptography. Some modern critics believe Eureka is the key to deciphering meaning in all Poe's fiction, that all his works involve similar theories." Wikipedia. Strange therefore, that the Christmas card possibly engineered by Zodiac should contain a cryptic message in the form of photocopied keys mailed from Eureka, California.
This is not the only time that Edgar Allan Poe may have played a part in a cryptic message mailed by the Zodiac Killer. It could have been the essay 'A Few Words on Secret Writing' that inspired the creation of the '13 Symbol' cipher mailed on April 20th 1970 by the Bay Area murderer. A cipher that was devised sometime between October 22nd 1969 and November 8th 1969, and belatedly mailed by the killer some 6 months later, with the accompanying text about the murder of San Francisco police officer Brian McDonnell on February 16th 1970. Secret Writing from our Secret Pal.      

Michael Cole wrote an excellent article entitled "My Name Is" Cipher Motivation that suggested the Zodiac Killer likely drew his inspiration for the '13 Symbol' cipher from an October 22nd 1969 newspaper article by Will Stevens, which laid down a challenge to the Zodiac Killer from the president of the American Cryptogram Association (ACA), Professor D.C.B. Marsh, to reveal his name. Apparently, several months later the killer duly obliged by opening his correspondence with the line "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...." 
He followed this by placing 13 characters underneath, widely believed to be the Zodiac Killer offering us his name. 
One couldn't help considering whether this cipher was not only created because of the newspaper article, but whether this cipher was created based on what was contained within the article- in particular the works of Edgar Allan Poe. This would be right up Zodiac's alley, devising a cipher based in the text of the newspaper article. 
Here is an excerpt "Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name-in cipher code-would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code, which will truly and honestly include his name."

We can see in the Edgar Allan Poe essay 'A Few Words on Secret Writing,' at the very beginning he shows the alphabet being split into two halves of 13 letters:
"Were two individuals, totally unpractised in cryptography, desirous of holding by letter a correspondence which should be unintelligible to all but themselves, it is most probable that they would at once think of a peculiar alphabet, to which each should have a key. At first it would, perhaps, be arranged that a should stand for z, b for y, c for x, d for w, &c. &c.; that is to say, the order of the letters would be reversed. Upon second thoughts, this arrangement appearing too obvious, a more complex mode would be adopted. The first thirteen letters might be written beneath the last thirteen, thus:
n o p q r s t u v w x y z
a b c d e f g h i j k I m; and, so placed, a might stand for n and n for a, o for b and b for a, &c. &c. This, again, having an air of regularity which might be fathomed, the key alphabet might be constructed absolutely at random." 

Quite fortunate that the Zodiac Killer, after possibly reading this newspaper article, should then create a cipher of 13 characters beginning with an A (the first letter of the alphabet) and ending with an M (the 13th letter of the alphabet), just like Edgar Allan Poe's construction in his essay 'A few Words on Secret Writing.'  
Throughout the newspaper article Professor D.C.B. Marsh is urging the Zodiac Killer to give his name, which clearly he wasn't going to achieve with such a limited number of characters, but he may have played a game with D.C.B. Marsh by offering us another cryptic message within the cipher. We contended previously that the 340 cipher and '13 Symbol' cipher were both likely created at the same time because of the interconnectivity between the two. The name Zodiac appeared to be numerically carried forward from the 20th line of the 340 to the '13 Symbol' cipher in the form of three circled 8's. This was achieved by placing the correct spelling of Zodiac alongside the 'near Zodiac' and numerically counting the difference between the columns. This produced perfect numerical symmetry, as did placing A to M (half the alphabet) alongside the '13 Symbol' cipher. For this to be achieved, it was argued the two ciphers must have been created with each in mind, and therefore both devised before November 8th 1969. See image here for explanation or read article 'Heaven Sent'.  
"In Christian numerology, the number 888 represents Jesus, or sometimes more specifically Christ the Redeemer. This representation may be justified either through gematria, by counting the letter values of the Greek transliteration of Jesus' name, or as an opposing value to 666, the number of the beast. "  
Wikipedia.
Curiously, if you visit the English gematria site here and enter Edgar Allan Poe into the calculator, 666 is achieved.    
​Was the Zodiac Killer playing games, giving us the name Jesus in the form of a numerical value and depicting himself as the savior of souls for the afterlife.

Professor D.C.B. Marsh attempted to coerce the Zodiac into giving us his name by stroking his ego- so it seemed rather unusual that every alphabetical letter within the '13 Symbol' cipher apart from one, could be found in the word 'NAME'. The Zodiac Killer gave us A twice, M twice, N twice and E once. The only exception was the letter K- the only letter the Zodiac Killer scrubbed out in the 340 cipher. Removing this from the '13 Symbol' cipher only leaves us with letters contained in the word NAME.
The creation of these two ciphers together is the only reasonable explanation for a correlation between the two (if one exists), and the inspiration of Edgar Allan Poe in the construction of the '13 Symbol' cipher, based upon splitting the alphabet down its center, was ultimately born from the article by Will Stevens.
​Edgar Allen Poe stated that "any cipher created by man can be solved by man."
Could it be that, any cipher created by Zodiac can be solved by Edgar Allan Poe.

This is a combination of previous articles (with a little extra) under one banner, attempting to dispel the idea that the 340 code is a genuine cipher, and all attempts at trying to reveal a continuous and coherent message will ultimately fail. 
By overwhelmingly consensus, the 340 cipher will soon be entering its 50th year unbroken, remaining impervious to all attempts at releasing its secrets, despite innumerable attempts by the best codebreakers and codebreaking machinery thrown at it. Either the Zodiac Killer created a cipher so stunningly impossible and misjudged the complexity of his cipher, or he didn't create one at all. The '13 Symbol' and '32 Symbol' codes were simply too short, with too many variables to be broken by conventional means. The '32 Symbol' cipher has 29 unique characters, meaning you can literally fill in the blanks however you choose. The '13 Symbol' cipher is simply too short to be called a cipher, and any solution proffered can be readily dismissed without a valid key. The Zodiac certainly wasn't stupid and must have known this- pouring huge doubt on whether he ever intended them to be solved in a conventional manner. Therefore, why should we treat the 340 cipher any differently. The whole thing just appeared to be one big game for the Zodiac Killer, as we huffed and puffed long into the night trying to pry open his ultimate masterpiece.
Many observers have wondered whether the Zodiac Killer mailed the 'code key' to the Vallejo Police Department on August 10th 1969 under the guise of a "concerned citizen," unaware that it had already been solved by Donald Gene and Bettye June Harden, as well as the FBI in Washington. Unusual that he should then sit on the 340 cipher for many years to come, able to resist the temptation of revealing his subsequent ramblings. Keeping a secret for nearly 50 years would certainly take great restraint from a killer who bathed in the spotlight.
The 340 cipher may very well have been designed in the mind of the killer as early as August 4th 1969, or the moment his 408 cipher was cracked. The decrypted 408 read: "I like killing people because it is so much fun it is more fun than killing wild game in the forest because man is the most dangerous animal of all to kill something gives me the most thrilling experience it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife." 
The answer to the 340 cipher probably already lay within the text of the 408 cipher- just designed in an altogether different format. The clue would later reveal itself in the design of the 'Halloween' card, mailed on October 27th 1970, where the killer placed "Paradice" and "Slaves" in a cross formation, and told us "sorry no cipher." This wouldn't be the only time the Zodiac Killer gave us clues, alluding to the fact we were chasing a solution to a cipher that didn't exist.        

One of the best finds in recent years was by Tahoe27, a regular contributor to the Zodiac Killer Site forum, who discovered a connection between a Tim Holt comic and the 'Halloween' card. Many features on the cover of the comic parallel the 'Halloween' card, including the wording By Fire, By Gun, By Rope and By Knife, along with "Redmask" (the skeleton eyes) and "Lady Doom" (peek-a-boo you are doomed). However, I believe Tahoe27 is not convinced that the 'Halloween' card was authored by the Zodiac Killer. 
If the 'Halloween' card was authored by an impostor, who based the 'Halloween' card on the Tim Holt comic, then are we to believe he was extremely fortunate that a year earlier, the real Zodiac Killer just happened to create a 340 cipher containing the word "BY" in all four corners of the cipher, along with PARADICE and SLAVES being a possibility, running down and across the cipher on the midpoint vertically and horizontally, just like the configuration on the 'Halloween' card.
Admittedly, the words paradice and slaves have not been proven to exist in the 340 cipher, but the fact they are a distinct possibility by comparison to the 'Halloween' card appears another very fortunate stroke of luck- particularly if we believe the author of the 'Halloween' card wasn't the Zodiac Killer- and only considered the Tim Holt comic in his design of the 'Halloween' card. If the 'Halloween' card was crafted by the Zodiac Killer using only the Tim Holt comic, then the above still applies.
The more likely conclusion we could draw from this, is that the 340 cipher was designed with the Tim Holt comic in mind, and the 'Halloween' card (one year later) was giving us a clue.  

​On the right, we can see how the four words "BY" fit into each quadrant of the 340 cipher just like the 'Halloween' card offering. What are the odds that in each quadrant of 80 characters we would find the letters B and Y together either horizontally or vertically every time. Not to mention the fortunate appearance of paradice and slaves bisecting the cipher perfectly. The killer may even have given us his signature in the bottom right corner, along with the running total, which was seven and counting on November 8th 1969.
If this wasn't the intended design of the 340 cipher, then either the Zodiac Killer or an impostor got extremely lucky, in just happening upon a Tim Holt comic that mirrored the 340 cipher unintentionally. But we may just be able to prove a definite link between these two communications and confidently state that both were designed by the Zodiac Killer, and with a fair degree of confidence, argue that the 340 cipher is not a cipher in the true sense of the word. The majority of the characters likely filler, but in this instance, far more than the 18 characters at the foot of the 408 cipher. The reason we may be able to contend the 340 cipher is not a continuous and uniform message like the 408 cipher (and not a cipher as we believe one to be), is because the Zodiac Killer lined us up for a fall and then admitted to it a year later.
On the 'Dripping Pen' card accompanying the 340 cipher, the killer stated
"This is the Zodiac speaking. I though you would nead a good laugh before you hear the bad news. You won't get the news for a while yet. Could you print this new cipher in your frunt page? I get aufully lonely when I am ignored, so lonely I could do my Thing." Was that bad news to come on October 27th 1970, when he mailed the 'Halloween' card.
If we believe that the 'Halloween' card design is referring back to the 340 cipher, then the message concealed on the envelope inner of "sorry no cipher," is the Zodiac Killer finally admitting that the 340 cipher is not the real cipher we had thought.
He is declaring that the 340 is "no cipher," and is in fact, based upon the paradice and slaves configuration. This is why he crosses the phrase "sorry no cipher" to mimic the design of paradice and slaves, using 13 letters in both instances.
The Zodiac Killer could easily have written "sorry no cipher" just the once, but deliberately fashioned it to form a link between the 'Halloween' card design and the 340 cipher.
After searching for solutions to the 340 cipher for nearly half a century, the Zodiac Killer may have given us the answer to its design after just one year, but it was overlooked. We have took the phrase "sorry no cipher" as an apology, that he wasn't giving us a cipher in the 'Halloween' card, when in actual fact, he was apologizing for stringing us along for the best part of a year, and offered us the real solution to the 340 cipher on October 27th 1970, contained within the 'Halloween' card. You could say it was a "trick" and "treat" befitting of Halloween.

​You will notice that the paradice and slaves configuration from the 'Halloween' card fits nicely into the 340 cipher.
The two dashes on the 10th line are represented by the letter S. 
The left-facing V on the 9th column and 10th line are represented by the letter E. 
​The two addition signs on the 9th column are represented by the letter A.
When the letter R of paradice is placed into its only conceivable position, along with the L and V from slaves, it is reminiscent of the 'Halloween' card. What are the chances that this could be achieved accidentally?  

The word paradice travels vertically 17 lines, exactly matching the 17 columns that slaves travels horizontally.The Zodiac Killer placed crosshairs beneath the 9th column, the midsection of the cipher (shown here).
The intersection on the 'Halloween' card configuration forms RAD and LAV, exactly the same as the bisecting center point of the 340 cipher. The Zodiac Killer also underlined the LAV of Paul Averly on the Halloween card envelope, on which he also placed the intersecting "sorry no cipher" on the envelope inner. 
The 'Halloween' card stamp depicts the surface of the moon with a half-earth in the distance and the words "In the beginning God." This phrase fits perfectly on the 1st line (the beginning) of the 340 cipher, with the 15th, 16th and 17th characters uncannily similar to the word GOD (the O in half phase just like the image on the stamp). 

But this wouldn't be the only correspondence that suggested the 340 cipher was designed as a puzzle rather than a 408 style message, If the paradice and slaves connection does exist between the 340 cipher and 'Halloween' card, then it makes more sense that the design of paradice and slaves was created in the 340 cipher first, and the 'Halloween' card was to "clue us in". If not, then the observation is just happenstance.
​If the 340 cipher doesn't actually contain a message, it will never be broken, and paradoxically will remain unsolved despite no solution being possible. 
The cipher has many other issues- in that, the Zodiac Killer may have had 'cipher three' formulated or drafted before he designed 'cipher two', to enable the interconnectivity between both. He had to think forwards to create backwards.
If we assume the 340 cipher has a solution and therefore a key (no matter how complex), then one may assume the Zodiac created the key, then created the message, and then applied the message to the key, so as to encrypt it. If this were the case, we must believe that the 'near Zodiac' that emerged on line 20 was by sheer chance. We would also have to believe, that had he crafted 'cipher three' completely independent of 'cipher two', with no intention of connecting both, then the following observations also happened completely by chance.

​Although covered many times before, the following will help explain the conundrum. 
Because the '13 Symbol' cipher was thirteen characters in total (half the alphabet) and began with an A and ended with an M, it was considered that by placing the first half of the alphabet alongside the '13 Symbol' cipher and numerically counting the difference between the columns, something may emerge- It did.
For example: C to N produces a difference of 11, whereas B and E produces a difference of 3. Non alphabetical symbols cannot produce a difference, so a zero is inserted. The resulting numbers produced have been color coded. The red section is before the first circled 8, the green section is after the last circled 8 and the blue section spans the first and last circled 8. Notice the perfect symmetry. The red and green numbers are identical read forwards or backwards, and the blue numbers again read identically in either direction, producing a mirror image.
An equally symmetrical pattern was created using the identical technique, when placing the correct spelling of Zodiac alongside the 'near Zodiac' on line 20 of the 340 cipher. 
Furthermore, the three 0's and three 8's created, can be combined and carried forward onto his '13 Symbol' cipher, which seemingly is what he did.
It is also apparent on the '13 Symbol' cipher, that either side of the three circled 8's are the Zodiac crosshairs and an inverted Aries symbol, also present on either side of the 'near Zodiac' on the final line of the 340 cipher. So, the author has effectively carried eight symbols from one cipher to another.
The point being, that when the Zodiac Killer sat down at his desk and began to create a unique key for his 340 cipher, into which he was to place his message, it accidentally created the 'near Zodiac' on the 20th line, accidentally created the correlation between 'near Zodiac' and Zodiac to produce three circled 8's, accidentally created the symbols either side of 'near Zodiac,' that fully or in part, carried forward to the '13 Symbol' cipher in the correct position, and accidentally created symmetry in both instances. Or, the Zodiac crafted the '13 Symbol' cipher before or alongside the 340 cipher, which I would argue nobody believes.
The Zodiac Killer may have began his 340 cipher key from the bottom first, deliberately allocating specific letters in his message to create the 'near Zodiac' characters and continuing from there. But, if the interconnectivity exists between the 340 cipher and '13 Symbol' cipher, he effectively began with 'cipher three' first and worked backwards, and worked forwards with the words ​paradice and slaves from the 408 cipher. 

​The Zodiac may have presented us with a fictitious negro male on August 4th 1969, who by inference, provided us with some valuable information about the Zodiac Killer driving his brown car by the payphone at Springs and Tuolumne. Was this a red herring of a clue, much like the correction on line 6 of the 340 cipher.
It can be clearly seen on the left, that the Zodiac Killer was conscientious enough to correct an alphabetical K to a reversed K on line 6, even though spelling correctly was never much of an issue with the Zodiac Killer. To validate that this was a genuine mistake, he made sure that the original K had not been fully obscured. This may give the impression it is easy to mix up your K's when implementing your encrypted text. Or maybe this is what he wanted us to believe. Who in their right mind would correct a fake cipher? Therefore it must be genuine.
Did the Zodiac Killer implement this correction, conveniently leaving the blacked out character still visible (and just reversing it), to give us the impression that the 340 cipher is undeniably genuine. Was this move just another red herring, to again validate something that never was. 
Alternatively, the final line of the 340 cipher may contain just a part message, yet incomplete, bearing in mind that many believe the '13 Symbol' cipher may contain some form of a name. The 340 cipher may end with: "the Zodiac is".... to be continued on the next cipher. The anticipation of the newspapers and readers alike, for the sequel to be released, would be a Zodiac dream.
The Zodiac Killer may have been pushing us in the right direction on October 27th 1970, but his attempt at revealing the workings of the 340 cipher may have begun far earlier, on December 16th 1969- just 38 days after his 'so called' masterpiece- in which he would be claiming a potential 38 more victims.
The December 16th 1969 'Fairfield' letter, mailed to the San Francisco Examiner, has been considered dubious Zodiac correspondence, however, it may have been Zodiac's first foray into revealing the mechanics of the 340 cipher, albeit using a rudimentary code as a tool. 
Clearly, the Zodiac must have known that offering just five different symbols in a code of nine is open to many different interpretations, and hence practically unsolvable. Therefore, one could suggest this wasn't his intention- he was simply teasing us with the mechanics of how the 340 cipher was designed, by using a rudimentary diagram based on the Tim Holt comic- and something he would expand upon nearly a year later.
One can see how he uses the Zodiac symbol around the crosshairs in the December 16th 1969 'Fairfield' letter code, implying a uniformity of message, but aligns five symbols as an introduction to this design. This marries perfectly with 'Death By Gun', 'Death By Knife', 'Death By Fire' and 'Death By Rope.' Death is the introduction, following by the methods of death around the crosshairs. This is exactly what he offered us on October 27th 1970, when he placed the methods of death in the four quadrants of the bisecting Paradice and Slaves.  Here is a representation. 

Another Fairfield letter was mailed prior to this correspondence on December 7th 1969, mailed to the San Francisco Chronicle. Was the Zodiac Killer highlighting pertinent sections of the 340 code in as little as one month after his November 8th 1969 'Dripping Pen' card and cipher, negating the idea he could resist the temptation of giving us clues to its design.
The final offering to the mechanics of the 340 cipher may have come with his final confirmed correspondence- that of the 'Exorcist' letter mailed to the San Francisco Chronicle on January 29th 1974. ​         

The symbols at the foot of the 'Exorcist' letter were rearranged by Kevin Robert Brooks to reveal the words "To Kill". The message would then read "If I do not see this note in your paper, I will do something nasty, which you know I'm capable of doing...To kill."  
This threatening message was very similar to the trinity of communications that began the Zodiac's letter writing campaign on July 31st 1969, where he stated "I want you to print this cipher on the front page of your paper. In this cipher is my idenity. If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend."  
In both the 'Exorcist' letter and July 31st communications the author would threaten "to kill'- as he would in the decoded 408 cipher. This is not particularly unusual for a serial murderer, but linking the unarranged symbols on the 'Exorcist' letter to the 340 code may connect yet another communication to the design of the cipher.
Key features of the 'Halloween' card, '13 Symbol' cipher, Fairfield communications and 'Exorcist' letter can be found in the 340 cipher, suggesting the Zodiac Killer was constantly pushing us towards the design of the 340 puzzle.
The following presentation will show a perceived correlation of the 'Exorcist' letter symbols to the only corrected section of the 340 cipher.

​​In the image on the left I have moved the two symbols on the extreme left of the 'Exorcist' letter to the right side as shown, without altering their position on the vertical axis. Then I have turned the extreme right symbol on the 'Exorcist' letter 90 degrees clockwise to form the new arrangement, shown in the bottom left image. This can now be compared to certain characters on the fifth, sixth, seventh line of the 340 cipher. The area in the proximity of the corrected sixth line.
Five of the six characters on the 'Exorcist' letter now bear a noticeable similarity to this area of the 340 cipher.
Did the Zodiac Killer sit down to create a uniform and continuous message using a code key in the 340 cipher, just like the message contained within the 408 cipher? If so, then the above findings were all created accidentally and unintentionally by the killer.
He placed an intersecting symbol at the center of the 340 cipher (+ sign), with two dashes at the periphery of the center line, to create the illusion of intersecting crosshairs.
Paradice and Slaves (uniformly of 17 characters) was created as a viable possibility bisecting the 340 cipher along the X and Y axis, along with "RAD" and "LAV" on the intersection of the cipher. The word "BY" (horizontally) was present in all four quadrants of the cipher. The 'near Zodiac' allied with the correct spelling of Zodiac on the 20th line produced the symmetry of three circled 8's. Using the identical technique and placing half the alphabet alongside the '13 Symbol' cipher, yet again, perfect symmetry was observed.
The three circled 8's, along with the symbols either side, all carried forward from the second cipher to the third cipher, and the 'Exorcist' letter symbols aligned with the corrected sixth line of the 340 cipher. This of course all happened by chance and the Zodiac Killer knew nothing about it.  
This would indicate that the Zodiac Killer had deliberately placed Paradice and Slaves into the 340 cipher, to which he would give us a clue one year later. The machinations of the '13 Symbol' cipher were most likely constructed in the mind of the killer before November 8th 1969, as to create a continuity between the two ciphers. The idea therefore, that the author of all these communications could interweave these designs together and still create a rambling uniform message to co-exist alongside them within the 340 cipher, would probably be a step too far.
The idea of a killer who sat down one evening to write a rambling 340 character message, to which he enciphered using a code key, who would then accidentally and inadvertently create so many by-products in his cipher without his knowledge, seems rather fortuitous. The Zodiac seemingly couldn't resist showing us the workings of his great masterpiece, and would eventually tell us that the 340 code was "no cipher", by giving us a portion of its true design in the 'Halloween' card on October 27th 1970. However, it's far more fun chasing chasing a real cipher, that will long continue for another 50 years.      

Here we will revisit an article published by the San Francisco Examiner on October 22nd 1969, in which Professor D.C.B. Marsh, president of the American Cryptogram Association laid down a challenge to Zodiac. The words he chose to use in this article may be the bedrock to much of the subsequent Zodiac communications, beginning with the 340 cipher, mailed only seventeen days after the San Francisco Examiner article. Here are the crucial extracts from that article.
'Dr Marsh told the Examiner today: "The killer wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts. He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name-in cipher code-would lead to his capture. I invite Zodiac to send The American Cryptogram Association a cipher code, which will truly and honestly include his name." It is difficult to believe that Zodiac, an avid reader of the newspapers, could resist such a challenge, particularly as he had promised to reveal his identity in the 408 cipher two months earlier, but failed to do so.  

The key section to note in the challenge by Professor D.C.B. Marsh is: "I invite Zodiac to send The American Cryptogram Association a cipher code, which will truly and honestly include his name."
Seventeen days later, the Zodiac Killer duly obliged with the November 8th 1969 340 cipher. Could this cipher have included the killer's name, but not in the format envisaged by Professor D.C.B. Marsh?
In a previous article entitled 'Zodiac Admitted 340 Not a Real Cipher' we examined the idea that the 340 cipher was inextricably linked to the Zodiac's 'Halloween' card, mailed on October 27th 1970. One can notice that the word "By" is located in each of the four quadrants of the 340 cipher. The author of the cipher also placed the letters F and K adjacent to one another no less than seven times (situated in each quadrant). But of particular interest was the corrected section on the sixth line of the 340 cipher, where the author chose to scrub out a forward facing K and replace it with a backwards K, elevated above the blacked out section.
The Zodiac Killer was known for numerous spelling errors in his communications, so why was it seemingly imperative to correct this one mistake? Was this correction crucial to the interpretation of the cipher, or was he drawing our attention to the letters in this section of the cipher? Are the F and K characters the initials of the Zodiac Killer?
This observation carries little merit on its own, so to bolster any argument for the initials of the Zodiac Killer being present in the 340 cipher, we have to explore the rest of his communications, particularly from around the time of the 'Halloween' card, in which we suggested was his admission that the 340 was unfortunately "no cipher". 
Linking the 'Halloween' card and 340 cipher through a Tim Holt comic book and explaining to us that the solution was "sorry no cipher." left us with the possibility that the 340 cipher was just a collection of puzzles, in which may have contained his name. The Zodiac Killer "wouldn't dare, as he claimed in letters to the newspapers, to reveal his name in the cipher to established cryptogram experts", but he may have given us the abridged version.
We now enter the crucial phase of Zodiac communications, from the '13 Hole' postcard mailed on October 5th 1970, to the 'Exorcist' letter mailed on January 29th 1974. This critical period of four consecutive communications, is probably key to understanding the message the Zodiac Killer was trying to push. That the 340 was "sorry no cipher."      

In the '13 Hole' postcard the Zodiac Killer stated "There are reports city police pig cops are closeing in on me. Fk I'm crackproof. What is the price tag now?"
This section of pasted letters was placed upside down. The question one should be asking is 'what is the purpose behind this'. If its significance had no relevance to the actual postcard, did it have relevance to another communication.
The wording "FK I'm crackproof" could indicate that the killer thought he was immune from capture, however, it could also be a reference to his 340 cipher once again. The word "crackproof" is something that is unable to be cracked.
The 340 cipher would certainly be impervious to cracking, and certainly resistant to the attempts of The American Cryptogram Association had the killer devised a cipher not of conventional understanding, of which Professor D.C.B. Marsh was hoping when he laid down the challenge. The F and K text being flipped on the '13 Hole' postcard reminds one of the flipped K (next to F) on the only corrected portion of the 340 cipher. If FK were the Zodiac Killer's initials, then he certainly could be declaring that he was crackproof. 
​Professor D.C.B. Marsh stated  "He knows, to quote Edgar Allen Poe, that any cipher created by man can be solved by man. Zodiac has not told the truth in his cipher messages to the Examiner, the Chronicle and the Vallejo Times-Herald. Zodiac has not done this, because to tell the complete truth in relation to his name-in cipher code-would lead to his capture." However, the Zodiac Killer could give his name in the form of initials without any fear of revealing his identity, and without risking his immediate capture. This may have manifested itself when he mailed his following cipher on April 20th 1970, when he opened with the gambit "This is the Zodiac speaking. By the way have you cracked the last cipher I sent you. My name is...."  The code placed underneath was likely an immediate rebuttal to this question. 

All he is probably doing, is stating "My name is FK," and once again telling us he is crackproof, just like the '13 Hole' postcard, which would be mailed five and a half months later. The phrase "FK I'm crackproof" fits perfectly in circular formation within the '13 Symbol' cipher- which itself contains a series of circled 8's. Structured in this fashion, the F and K yet again align, as does the K and M in both the cipher and phrase. 
Continuing with our four consecutive communications from October 5th 1970 onward, we now have the October 27th 1970 'Halloween' card promising to yet again reveal his name: "I feel it in my bones, You ache to know my name, And so I'll clue you in." Again we feel disappointed only to see the word "Boo" on the card inner- but we know the Zodiac Killer isn't going to make this a conventional and straightforward offering. He offers us the phrase "sorry no cipher," but can we find his name or initials within this communication. This is where it gets more difficult, nevertheless, we are aware that within the '13 Hole' postcard he reversed or flipped the text containing "FK I'm crackproof" and he flipped the K (next to the F) on the sixth line of the 340 cipher. So the obvious conclusion, is to look for flipped or reversed text within the 'Halloween' card.  

The only place that F and K exist within one word on the 'Halloween' card, is in the word "knife." either side of the reversed letter N.
If we flipped the reversed N back to its appropriate position, the F and K of "knife" would be reversed yet again.
Now let us turn our attention to the peculiar configuration at the foot of the card inner. It would be extremely satisfying for the 'Halloween' card to read "I feel it in my bones, You ache to know my name, And so I'll clue you in... FK,"- so that is what we will create, by manipulating this card to read whatever we want it to.
The strange symbol, reading it as true as possible, appears like a number 7, followed by four dots and the letter F.
7+4=11=K (followed by F).
Without further ado, we shall move on to the next confirmed Zodiac communication on March 13th 1971, in which the Zodiac stated "This is the Zodiac speaking. Like I have allways said, I am crack proof. If the Blue Meannies are evere going to catch me, they had best get off their fat asses + do something. Because the longer they fiddle + fart around, the more slaves I will collect for my after life. I do have to give them credit for stumbling across my riverside activity, but they are only finding the easy ones, there are a hell of a lot more down there. The reason I'm writing to the Times is this, They don't bury me on the back pages like some of the others."
You will notice that the Zodiac Killer refers to "crackproof" once again, parroting his October 5th 1970 communication five months earlier. However, he doesn't just state he is crackproof, he reminds us that he has always been telling us he is crackproof, and quite possibly we just haven't got the message.

Roll on the January 29th 1974 'Exorcist' letter, signed "yours truley," nearly three years later, giving us our final installment of FK contained within the array of symbols at the foot of the letter. 
On this occasion he mirrors the sixth line of the 340 cipher by elevating the K above the letter F, and to its left. In fact, five characters from the Exorcist letter can be found in and around the corrected sixth line of the 340 cipher, as shown here in a previous article. This was possibly the fourth consecutive communication inferring an FK link and the suggestion that the author was indeed "crackproof."  
Was this a persistent and deliberate attempt to be true to the challenge laid down by The American Cryptogram Association and Professor D.C.B Marsh, by inserting his name (albeit initials) into the 340 cipher and subsequent communications, or just a case that my mind is F@@Ked after six exhausting years of looking for patterns where none exist.

In 2013 Tahoe27 made an excellent discovery, possibly linking the 'Halloween' card with a Tim Holt comic featuring the 'Wheel of Fortune' or 'Rota Fortunae.' The cover displayed the four methods of death used by Zodiac on his 'Halloween' card configuration, that of 'Death By Gun', 'Death By Knife', 'Death By Fire' and 'Death By Rope'. However, the discovery may be far greater than first considered, with the 1952 Tim Holt comic the source behind the design of the 340 cipher rather than the Halloween card. The 'Halloween' card was just the confirmation that the 340 was not a cipher at all, hence the crossed "sorry no cipher" addition on the inside of the envelope, linking the Paradice and Slaves configuration back to the November 8th 1969 offering.
​See 'Zodiac admitted 340 not a real cipher' [pt1].' 
The Zodiac Killer may have been pushing us in the right direction on October 27th 1970, but his attempt at revealing the workings of the 340 cipher may have begun far earlier, on December 16th 1969- just 38 days after his 'so called' masterpiece, claiming a potential 38 more victims.
The 'Fairfield' letter has been considered dubious Zodiac correspondence, however, it may have been Zodiac's first foray into revealing the mechanics of the 340 cipher, albeit using a rudimentary code as a tool. There are two key features of this correspondence possibly linking it to the 'Halloween' card, and more importantly, to the Tim Holt comic. The second we will deal with later, but the first is the rather childish looking or amateurish offering of a code consisting of only nine characters.
Clearly, the Zodiac must have known that offering just five different symbols in a code of nine is open to many different interpretations and therefore practically unsolvable. Therefore, one could suggest this wasn't his intention- he was simply teasing us with the mechanics of how the 340 cipher was designed by using a rudimentary diagram based on the Tim Holt comic- and something he would expand upon nearly a year later.
One can see how he uses the Zodiac symbol around the crosshairs in the 'Fairfield' letter code, implying a uniformity of message, but aligns five symbols as an introduction to this design. This marries perfectly with 'Death By Gun', 'Death By Knife', 'Death By Fire' and 'Death By Rope.' Death is the introduction, following by the methods of death around the crosshairs. This is exactly what he offered us on October 27th 1970, when he placed the methods of death in the four quadrants of the bisecting Paradice and Slaves.  Here is a representation. 

The November 8th and 9th 1969 communications came as one package, and he certainly wasn't going to reveal the workings of the 340 cipher after just one day in the 'Bus Bomb' letter, so the December 16th 1969 (or possibly December 7th 1969) 'Fairfield' communication was effectively the Zodiac Killer's first communication after the 340 cipher. Can we again call it coincidence that, not only did the Fairfield offering give us a further code, but 'Death By Gun', 'Death By Knife', 'Death By Fire' and 'Death By Rope' would fall readily into its design, as would the 'Halloween' card configuration of Paradice and Slaves so readily mirror the 340 cipher- possibly bringing these three communications in line with one another. The second interesting feature of the Fairfield letter is the wording the author uses:
"This is the Zodiac speaking. I just want to tell you this state is in trouble. I will go for the Goverment life, so don't foreget me. I will kill more people than you cops can count, so look for more blood. You better print."     

The 'Halloween' card has become synonymous with either a threat of a fourteenth victim or the claim of a fourteenth victim, however, the number four may hold more significance within its design. The eyes are obviously of great importance to the Zodiac Killer- after all, he added twelve to the card inner, along with 4-TEEN and the unusual symbol.
He deliberately chose to separate fourteen, creating the number 4. He added four larger eyes outside of the tree, as well as placing four dots around the symbol. He also highlighted four eyes in red on the card outer and inner. 
The strange symbol (with the four dots) could be a joined Z, V and F, and being preceded by four eyes, could simply be interpreted as "look for Zodiac victim fourteen" or with respect to 4-TEEN, "look for number fourteen." 
Up to this point and beyond, none of Zodiac's confirmed or insinuated victims (Kathleen Johns, Cheri Jo Bates and Richard Radetich) lay undiscovered, so it is entirely plausible this card was referring to the disappearance of Donna Ann Lass 51 days earlier. The skeletons indicative of a body lain undiscovered for a measurable period of time.
The coloring of the four skeleton eyes may be suggestive of blood or death, a formula used in the creation of the '13 Hole' postcard on October 5th 1970, where the author added a pasted red crucifix to the card.
The 'Halloween' card could be telling us to "look for Zodiac victim fourteen" or equally "look for blood," as did the Fairfield letter on December 16th 1969, when the author stated "I will kill more people than you cops can count, so look for more blood. You better print."
This discovery by Tahoe27 on December 30th 2013 was certainly a great find, but it may just turn out to be the greatest find of them all. A discovery that may finally reveal the 340 offering to be masquerading as a fully fledged cipher, and as such, has had us chasing our tails for nearly half a century. Albeit, undecipherable at the time, the answer was probably staring us in the face just 38 days after the November 8th 1969 communication- in a letter many thought was penned by a hoaxer.

Courtesy of Zodiac Killer Site forum. These envelopes have been cleaned up using editing tools. 

This is a continuation from the previous article 'Zodiac Admitted 340 Not a Real Cipher.'
You will notice that the paradice and slaves configuration from the 'Halloween' card fits nicely into the 340 cipher.
The two dashes on the 10th line are represented by the letter S.
The left-facing V on the 9th column and 10th line are represented by the letter E.
​The two addition signs on the 9th column are represented by the letter A.
When the letter R of paradice is placed into its only conceivable position, along with the L and V from slaves, it is reminiscent of the 'Halloween' card. What are the chances that this could be achieved accidentally?  

The word paradice travels vertically 17 lines, exactly matching the 17 columns that slaves travels horizontally.The Zodiac Killer placed crosshairs beneath the 9th column, the midsection of the cipher (shown here).
The intersection on the 'Halloween' card configuration forms RAD and LAV, exactly the same as the bisecting center point of the 340 cipher. The Zodiac Killer also underlined the LAV of Paul Averly on the Halloween card envelope, on which he also placed the intersecting "sorry no cipher" on the envelope inner. 
The 'Halloween' card stamp depicts the surface of the moon with a half-earth in the distance and the words "In the beginning God." This phrase fits perfectly on the 1st line (the beginning) of the 340 cipher, with the 15th, 16th and 17th characters uncannily similar to the word GOD (the O in half phase just like the image on the stamp). 

Many have questioned whether the 340 cipher was a genuine offering by the Zodiac Killer, designed to reveal a complete message similar to the 408 cipher- and did the Zodiac Killer hide the key to the 340 cipher in one of his other communications? The answer to the last question is almost certainly yes, but the answer to the first question is almost certainly no. The Zodiac Killer actually admitted in one of his correspondences that the 340 code was not a cipher. 
One of the best finds in recent years was by Tahoe27, a regular contributor to the Zodiac Killer Site forum, who discovered a connection between a Tim Holt comic and the 'Halloween' card. Many features on the cover of the comic parallel the 'Halloween' card, including the wording By Fire, By Gun, By Rope and By Knife, along with "Redmask" (the skeleton eyes) and "Lady Doom" (peek-a-boo you are doomed). However, I believe Tahoe27 is not convinced that the 'Halloween' card was authored by the Zodiac Killer. 
If the 'Halloween' card was authored by an impostor, who based the 'Halloween' card on the Tim Holt comic, then are we to believe he was extremely fortunate that a year earlier, the real Zodiac Killer just happened to create a 340 cipher containing the word "BY" in all four corners of the cipher, along with PARADICE and SLAVES being a possibility, running down and across the cipher on the midpoint vertically and horizontally, just like the configuration on the 'Halloween' card.
Admittedly, the words paradice and slaves have not been proven to exist in the 340 cipher, but the fact they are a distinct possibility by comparison to the 'Halloween' card appears another very fortunate stroke of luck- particularly if we believe the author of the 'Halloween' card wasn't the Zodiac Killer- and only considered the Tim Holt comic in his design of the 'Halloween' card. If the 'Halloween' card was crafted by the Zodiac Killer using only the Tim Holt comic, then the above still applies.
The more likely conclusion we could draw from this, is that the 340 cipher was designed with the Tim Holt comic in mind, and the 'Halloween' card (one year later) was giving us a clue.    

On the right, we can see how the four words "BY" fit into each quadrant of the 340 cipher just like the 'Halloween' card offering. What are the odds that in each quadrant of 80 characters we would find the letters B and Y together either horizontally or vertically every time. Not to mention the fortunate appearance of paradice and slaves bisecting the cipher perfectly. The killer may even have given us his signature in the bottom right corner, along with the running total, which was seven and counting on November 8th 1969.
If this wasn't the intended design of the 340 cipher, then either the Zodiac Killer or an impostor got extremely lucky, in just happening upon a Tim Holt comic that mirrored the 340 cipher unintentionally. But we may just be able to prove a definite link between these two communications and confidently state that both were designed by the Zodiac Killer, and with a fair degree of confidence, argue that the 340 cipher is not a cipher in the true sense of the word. The majority of the characters likely filler, but in this instance, far more than the 18 characters at the foot of the 408 cipher. The reason we may be able to contend the 340 cipher is not a continuous and uniform message like the 408 cipher (and not a cipher as we believe one to be), is because the Zodiac Killer lined us up for a fall and then admitted to it a year later.
On the 'Dripping Pen' card accompanying the 340 cipher, the killer stated
"This is the Zodiac speaking. I though you would nead a good laugh before you hear the bad news. You won't get the news for a while yet. Could you print this new cipher in your frunt page? I get aufully lonely when I am ignored, so lonely I could do my Thing." Was that bad news to come on October 27th 1970, when he mailed the 'Halloween' card.
If we believe that the 'Halloween' card design is referring back to the 340 cipher, then the message concealed on the envelope inner of "sorry no cipher," is the Zodiac Killer finally admitting that the 340 cipher is not the real cipher we had thought.
He is declaring that the 340 is "no cipher," and is in fact, based upon the paradice and slaves configuration. This is why he crosses the phrase "sorry no cipher" to mimic the design of paradice and slaves, using 13 letters in both instances.
The Zodiac Killer could easily have written "sorry no cipher" just the once, but deliberately fashioned it to form a link between the 'Halloween' card design and the 340 cipher.
After searching for solutions to the 340 cipher for nearly half a century, the Zodiac Killer may have given us the answer to its design after just one year, but it was overlooked. We have took the phrase "sorry no cipher" as an apology, that he wasn't giving us a cipher in the 'Halloween' card, when in actual fact, he was apologizing for stringing us along for the best part of a year, and offered us the real solution to the 340 cipher on October 27th 1970, contained within the 'Halloween' card. You could say it was a "trick" and "treat" befitting of Halloween. 
However, there is still a little more to find regarding the methods of death and how they configure within the 340 itself- so the search is not over yet.
ZODIAC ADMITTED 340 NOT A REAL CIPHER [PT2]

​Cipher Explorer tool below, courtesy of Zodiac Killer Ciphers. 

The Zodiac Killer did not mail the three July 31st 1969 letters to the San Francisco Examiner, San Francisco Chronicle and Vallejo Times-Herald, although the murderer of Betty Lou Jensen, David Faraday and Darlene Ferrin certainly did. 
In the letter to the Chronicle, the author suggested that within the code he had mailed we would discover his identity.
He wrote "Here is part of a cipher the other 2 parts of this cipher are being mailed to the editors of the Vallejo Times and SF Examiner. I want you to print this cipher on the front page of your paper. In this cipher is my idenity. If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend." 
When the cipher was decoded a matter of days later, the code revealed "I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerous animal of all to kill something gives me the most thrilling experence it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves. I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife." 
The killer of three assured us that his identity was concealed within the cipher, while all along, knowing the enciphered text would reveal that he was unprepared to give us his name. He was effectively equating his identity with his name, not with his pseudonym or other covert means of identifying him. That is probably because the assailant at Lake Herman Road and Blue Rock Springs was technically not the Zodiac Killer. The "Zodiac Killer" 'only' killed two people under the Zodiac pseudonym, that of Cecelia Shepard and Paul Stine.
As covered in a previous article 'Born on August 3rd,' it was argued that the killer had no "identity" or pseudonym to reveal to us before August 3rd 1969, because he hadn't yet assigned one to himself. Being called the 'code killer' or 'cipher killer' in the newspapers clearly didn't sit well with an ego-driven murderer. He had to give himself a pseudonym worthy of his perceived stature- hence, the "Zodiac Killer" was born. 

​The San Francisco Sunday Examiner and Chronicle of August 3rd 1969 opened with the lines "A self-accused killer failed to keep a threat of mass murder here, but there was no slackening of tension or mystery caused by the warning. The police department telephone system was clogged at times by anxious callers asking if the "cipher killer" had been caught."  The next day the killer would waste no time in introducing us to his new identity or pseudonym, opening with the line "This is the Zodiac Speaking." In other words, looking for his identity in the 408 cipher, in either the enciphered or decoded version would be a futile exercise, because he certainly wasn't going to reveal his real name, and it is extremely likely he had no identity or pseudonym at this juncture. Had he already attributed himself the pseudonym "Zodiac" prior to the July 31st 1969 letters, then this threefold barrage was the perfect time to announce the menacing "Zodiac" to the world, something he clearly failed to do. In fact, he could only muster the unoriginal "This is the murderer of the 2 teenagers last Christmass at Lake Herman + the girl on the 4th of July near the golf course in Vallejo."  
​Four days later however, he would be triggered into action by the lame 'cipher killer' pseudonym designated to him by the public and featured in the San Francisco Sunday Examiner and Chronicle of August 3rd 1969- He was in control, and as such, was not going to be labelled by anybody.
It was now a simple task of replacing one word in his introduction, from "This is the murderer" to "This is the Zodiac." 
This would have significant implications regarding the Riverside murder of Cheri Jo Bates on October 30th 1966, and in particular the three Bates letters. The idea that the symbol on these letters was an alphabetical Z indicating Zodiac would now be nullified, as the Zodiac pseudonym was 827 days in the making. 

Had the murderer opened up with the 340 cipher on July 31st 1969 rather than the 408 cipher, then the statement "in this cipher is my identity" would have had very few detractors, when just four days later a further communication arrived stating "This is the Zodiac Speaking." 
Comparing this introduction to the 'near Zodiac' at the foot of the 340 cipher would have left few in doubt this was deliberately placed, and indeed, he had concealed his identity in the cipher.
However, because the 340 cipher was mailed on November 8th 1969, it is often argued that the 'near Zodiac' may have fell out accidentally on his creation of the cipher- something that would likely never have been argued three months earlier. 
Therefore, if the Zodiac Killer did belatedly give us his identity or pseudonym in the second cipher, when we already knew it, one could suggest it has a secondary purpose, other than to be deciphered in exactly the same way as the other 334 characters.  
There is a growing perception that the 340 cipher is effectively a "bag of puzzles" rather than a continuous uninterrupted message, as many of its features can easily be linked or shown to compare favorably with other correspondences mailed by the Zodiac Killer. This man wasn't a Professor Moriarty style genius- so he either created a method of encryption so illogical, as to make the cipher unsolvable by the logical mind or computer created by logic, he created a mix of puzzles disguised within the cipher, or he created the perfect ghost cipher, to which he would eventually keep his promise by placing his identity within a cipher, but little else. 
Without identifying a key and demonstrating which communication it was found, then the '13 Symbol' and '32 Symbol' ciphers are simply too short to ever be proven as solved. In a previous article we highlighted a piece by Dave Oranchak, in which 46 consecutive alphabetical letters from the historical text of Edward Hyde, Earl of Clarendon, can be placed successfully into a portion of the 408 cipher. Dave Oranchak, the foremost expert on the Zodiac ciphers, commented on this "So, only one piece of text, from a vast collection of eleven billion pieces of text, fit into this chunk of cipher text. A one in eleven billion chance seems to suggest some significance. But don’t be fooled by this. Just because this rare event occurred, doesn’t mean it is anything more than a simple coincidence. If we didn’t already know the real solution to the 408, how do we know that this chunk of old and obscure text isn’t the correct solution?"  
Therefore, one can easily see the multiple solutions that can be harvested from these inadequately designed ciphers. The Zodiac Killer wasn't a genius, but he certainly wasn't a fool either, and must have known that the variability of the '32 Symbol' cipher, and lack of characters within the '13 Symbol' cipher were open to multiple solutions. This was probably part of the fun.
The man, eventually to become known as the Zodiac Killer, mailed the 408 cipher on July 31st 1969. This was a genuine cipher, decoded by Donald Gene and Bettye June Harden of Salinas, California, who both used homophonic substitution to identify the solution. The "cipher killer" or "code killer" would not have lived up to the name given him by the San Francisco Sunday Examiner and Chronicle on August 3rd 1969-  the "killer of codes" would have been far more suitable.