Lets take a closer look at the letter which accompanied the Z 340 Cipher. There appears to be a lot more going on here that confirms the idea that the composition provides a key for the cipher. Starting with the register mark, which he uses in a variety of ways, in this and other letters, expanding the circle from the center to align with the first set of significant points on the circumference, one can see how the ending ‘g’ of the word ‘Thing’ has been emphasized by geometry in the composition. The circle also includes the number of victims. And look at how the word ‘Thing’ in the card has been underlined by the same circle, below. The two words Thing are being linked, one pre-printed at the center (left) of the greeting card and one added and made bold by the Zodiac. The emphasis, linking and centering of the word indicate it is of prime importance to the meaning of the composition.
Accordingly, I have boxed the pre-print ‘Thing’ to show its importance. As soon as I do another pattern pops out. Using the blue line I show how it sits aligned with the ‘PS’. at the center of the main body of text. Underlining each line of text in yellow we can see there are 6 lines above and six below. These I’ve numbered. Now the lines around his own bolded word take on added significance. He wants to direct attention, however subtly, to the lines around his own bolded word ‘Thing’. There we see again the same 6 lines below and 6 lines…somewhat disguised as exclamation points…this time placed to the right.
The red rectangle attaches to many points, extended to the bottom of the page (the border being used as a part of the composition as it is often in paintings). It is meant to call out the words ‘my Thing’ and again the two 6 line groupings. Note how the text all sloping in relation to the page straightens in a seemingly awkward attempt to align with the center of the target symbol. The tops of the exclamation points, aligned, appears to be very deliberate and forced. And note how the right side vertical rectangle edge aligns with the ‘J’ of July and the ‘O’ of Oct. The red arrows and the black curve to the left (see above) are more signs that everything within the rectangle has been very carefully arranged. And the letter, stripped of all other guidelines, indicates very clearly that we are to focus on the lower left quadrant of the cipher. By the way, the layout below the target symbol recalls the one placed on the door of the Carmen Ghia at Lake Berryessa, perhaps as a chilling reminder of the murder the previous July.
Very likely a light table was used here and various templates and/or guidelines were traced over. The ellipses (in black) have been used to arrange the text above. Note how it affects the spacing- beginnings and endings of words are aligned along the ellipse edges. The curves intentionally lead the eye again to the ‘g’ in the bolded word Thing where they intersect at their bottoms.
The composition however is simultaneously designed to convey information and to deceive. As with all his letters the writer appears to be somewhat of an idiot and that prevents us from thinking he’d have the smarts to use geometry in such an intelligent and sophisticated manner. The spacing and slanting of the text makes it seem he is perhaps even insane as it appears devoid of logic- haphazard. These are time honored techniques for hiding coded messages- used at least since the Elizabethans. He’s laid out the instructions for the Z 340 here- but it’s easy to be deceived by the idiocy of the style- you’ll never find it without having studied, and taught, geometry in composition over a lifetime as I have. He’s done it so well it has remained hidden for almost 50 years. I’m not saying I’m more intelligent than anyone who’s ever tried to crack the 340. Its just that I happen to share a particular skill set with the writer. But I am somewhat surprised nobody has analyzed the letter to this degree before…where one might expect a key would naturally be provided.