When the Button Letter was mailed on June 26th 1970, the Zodiac Killer gave us a map of San Francisco and Vicinity with his crosshairs centered over Mount Diablo, stating "the map coupled with this code will tell you where the bomb is set." If we were to find a perceived bomb, it is fairly obvious we have to travel a certain angle and distance from the top of Mount Diablo to find the location. Therefore, the 32 symbol code, if it served any purpose whatsoever, had to contain a measurement in the form of degrees and distance. The map scale was 6.4 miles to the inch - so that will be the distance the Zodiac Killer has to employ from Mount Diablo to make any sense. The degrees he used was radians, because he told us so in the July 26th 1970 Little List Letter. The Zodiac stated "P.S. The Mt. Diablo code concerns Radians + # inches along the radians". He is actually telling us that the 32 symbol code contains radians and inches in the solution.
"P.S. The Mt. Diablo code concerns (is about ) (has to do with) Radians + # inches along the radians". Any cipher expert such as David Oranchak, or quite frankly, any Joe Bloggs such as myself, will tell you that a 32 symbol code with only three repeating characters is unsolvable without a key. The Zodiac Killer was certainly no muppet - and clearly knew this when he concocted this jumble of random characters. But he gave us the key a mere 31 days later in the form of an arrow and a hashtag. He even gave us the answer of "Radians and # inches along the radians" on a separate line to distinguish the very fact. He then began the first "Radians" with a capital letter to emphasize this. We just had to key in the number. The symbol # is most commonly known as the number sign, The symbol is described as the "number" character in an 1853 treatise on bookkeeping, and its double meaning is described in a bookkeeping text from 1880. The instruction manual of the Blickensderfer model 5 typewriter (c. 1896) appears to refer to the symbol as the "number mark". Some early-20th-century U.S. sources refer to it as the "number sign", although this could also refer to the numero sign. A 1917 manual distinguishes between two uses of the sign: "number (written before a figure)"; and "pounds (written after a figure)". Mainstream use in the United States is as follows: when it prefixes a number, it is read as "number", as in "a #2 pencil" (indicating "a number-two pencil"). The one exception is with the # key on a phone, which is always referred to as the "pound key" or "pound". Thus instructions to dial an extension such as #77 are always read as "pound seven seven". Wikipedia.
The answer was now extremely simple. All we had to do was insert a number in place of the hashtag, shown by the big flashing arrow pointing us in the right direction. The hashtag conveniently preceded "inches", so it's here we will slot in the number 5 - and bingo - we have our answer to the devilishly difficult 32 Symbol Cipher: "Radians + 5 inches along the radians" or "Radians and 5 inches along the radians". By some quirk of fate, this phrase with the addition of the number 5, just happens to be exactly 32 characters in length. What an absolute criminal mastermind the Zodiac Killer was, creating a code that we only had to add one character to. As with all the best puzzles, the answer is usually hidden in plain sight. There is a possibility that the code reads "4 radians and 5 inches along the radian", but because the Zodiac Killer inserted one hashtag, it is more likely this is the only addition required.
With 29 unique characters in a 32 character code, any correlation between the characters and alphabetical solution is going to be minimal. What we do have in the solution above, is no word running from one line to the next, with the letter C beginning the word radians at the start and end of the code. As with any cipher, the Zodiac Killer had the opportunity to provide us with a key in later communications, which he effectively did for cipher 2, 3 and 4 when he gave us the answers literally word for word. What we have to consider are the three "cryptic messages" he gave us in three consecutive communications from July 26th 1970 to October 27th 1970. The Zodiac Killer was giving us the solutions to the ciphers before his campaign ended, albeit he wanted us to put in a modicum of effort. He told us on July 26th 1970 that the Mount Diablo code concerns "radians and 5 inches along the radians" verbatim. He then gave us the cryptic "Fk I'm crackproof" that fortunately slots nicely into the 13 Symbol Cipher in a cyclical nature. And finally, he gave us "paradice and slaves" in a cross formation (17X17) that mimicked the 340 cipher formation exactly (adding sorry no cipher in the identical formation on the Halloween envelope inner). How can three consecutive "cryptic messages" just happen to seamlessly fall into each cipher with no effort required?
We can place thousands of names into the 13 Symbol Cipher and then attempt to justify why this is correct by providing additional information on the subject. There have been hundreds of "solutions" to the 340 cipher, when we know only one can realistically be correct. This demonstrates the subjectivity of the 340 cipher to conform to what you had already decided upon before the decoding process began. You have the predetermined answer in your head and work towards that goal to the exclusion of all others. Our own biases will govern the answer we require. The 32 Symbol Cipher is too character variable to be decoded using standard cryptographic techniques, and therefore can literally give rise to an infinite number of possibilities, requiring only three characters to match. What better way to solve the ciphers than straight from the horse's mouth. The Zodiac Killer supplied us with 32 characters in the Little List Letter, 14 characters in the 13 Hole Postcard (that began and ended in the same letter), and 13 characters in the Halloween Card - all of which required no 'square pegs in round holes' technique to land unadulterated into every cipher. The notion of a braggart remaining tight-lipped about his ciphers, while still staggering around the streets of America some 50 years later, deserves a book all by itself.
THE CODE SOLUTIONS BY ZODIAC