I think it’s very possible Z was unaware that a short code could not be verifiable.

Texas Sharpshooter Fallacy applies here. A guy does some target practice on the side of an old barn. When he’s done shooting, he walks over and paints a bullseye around where most of the bullets hit.

My uncle was an old treasure hunter (I’m serious) and in interviews when they would ask "how come you haven’t found the treasure yet?" He would sincerely say "well, that’s how smart those bastards were"

What an idiot.

I do think it’s possible Z engaged in other types of codes and meanings – but not to some superhuman degree.
The halloween card strikes me as a loose collage about his crimes – but not a super / master code beyond all comprehension.

He’s pulling things from various sources like an enthusiast would – not an expert. His focus was loose, his references diverse, he was a dabbler.

A few years ago I looked at the symmetry exhibited in the 13 Symbol cipher because of the way it was arranged and organised. It was apparent that the code had traits of half the alphabet, beginning with A and ending with M. When the first half of the alphabet was lined up alongside the Z13 and we simply counted the alphabetical difference between the columns numerically, extremely good symmetry emerged in the resulting numbers.
Where two alphabetical letters didn’t exist in a column, a zero was inserted, because no number could be generated.

At the beginning of the April 20th 1970 correspondence, the Zodiac stated have you cracked the last cipher I sent you? Believing these two ciphers may be interconnected, I looked at the near-Zodiac on the final line. I couldn’t place the alphabet alongside it, but the obvious choice in this instance was to place "Zodiac" alongside. Using the identical technique to the one described above, the numbers 000888 emerged, giving rise to the notion of three circled 8’s. In essence, they appeared carried from cipher 2 to cipher 3.

This wasn’t a case of choosing random words to manufacture symmetry, the reason for placing the half-alphabet alongside Zodiac’s 13 Symbol cipher can be justified since it begins with A and ends with M. The reason for placing Zodiac alongside the near-Zodiac is self explanatory. Both are the obvious choice. In both instances, the same technique produced symmetry, rivalling the symmetry evident in the original code.

"the near-Zodiac "

It reads "Zo?aik"

According to butterfield site.

“Zodiac” is derived from the Greek word “zodiakos,”

http://zodiackillerfacts.com/zodiac-letters/zodiac-the-astrological-zodiac/

At ZodiacKiller.com it was put forth that the "My name" cipher resembles the letters written on "Temple of Poseiden"

http://www.zodiackiller.com/MyNameIs.html

Lots of potential Greek influences

Karl F. Werner ?

Karl F. Werner ?

Werner was ruled out based on alibis.

I also doubt that all the symbols in z13 map to individual plaintext characters. The circled 8s don’t appear in any other ciphers and the author probably knew that a length of 13 characters would make it unsolvable. I came up with this interpretation: https://www.zodiackillersite.com/viewto … =81&t=5153

The approach described in the linked post needs to be reviewed (please let me know if I’m crazy ) but if we accept it for now, I think z13 means one or all of
1 – "MR HARDEN" (a continuation of "My name is ___". An attempt at misdirection or a joke)
2 – "TRY HARDER" (telling the reader to keep trying/try something else)
3 – "TRY HARDER, MR HARDEN" (same message as above but directed at the guy who solved his last cipher)