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 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."