I’m new to this. But I think I’ve got a cross-puzzle solution among the Z13, the leftover letters of Z408, and a little more of the RH signature on the Riverside desktop poem.

Stop me if you’ve heard this one before. Or it just sucks. Like I said, I’m new. I’ll start with the solutions.

Z408 Leftovers
Solution: Meet Robeet the Hipie

Leftover letters:
EBEORIETEMETHHPITI

Method:
Step 1: Do substitution (i.e. the Harden solution)
Step 2: Collect and unscramble the extra letters (i.e. anagram)

Z13, aka: "My Name Is" cipher
solution: ROBHTHEHIPPIE

Step 1: Do substitution
Step 2: Unscramble the letters (i.e. anagram)

Riverside poem:
Possible solutions:
Rob H
Robert H
Rob (the) HIppie
Robert (the) Hippie

The most important insight is about these 2 words: "the hippie."
1) Zodiac liked to use the word "hippie."
2) It was fashionable slang in that area, particularly in Berkeley, at the time (obviously).
3) It’s pretty easy to pick out "hipie" or "the hipie" as (a) possible word(s) by un-jumbling the Z408 leftovers.
4) most crucially to the codes: the words solve what Mr. Oranchak has identified as one of the Z13’s curiosities/difficulties: the high number of repeated symbols/letters appearing in a code with so few total symbols/letters.
– The Z13 has 13 symbols/letters
– Of those symbols, there are 3 cases of pairs of the same symbol. There is, in addition, a triplet of the same symbol. So 9 of the 13 letters in the solution are taken up by a trio of pairs plus a single triplet. (This assumes that one symbol/letter in the cipher equates to 1 single letter in the solution (and only that one letter). I’m also assuming that there is an anagram to be solved after the letters are figured out. It’s one of the simplest approaches, and I’m new at this.)
5) In the words "the hippie" there are 4 letters that appear twice in 9 total letters. Using "the hippie" as part of the solution would mean:
– The 3 pairs would be completed.
– 2 out of 3 of the letters of the additional triplet would be completed.
– We would only need to use 1 of the letters from the pairs 1 more time in the remaining 4 spots to create the triplet and thereby complete the repeating letters.
6) Therefore, using "the hippie" in the Z13, a favorite word of Zodiac, would go a long way to explaining/relieving the frequency of, and space taken up by, repeated symbols/letters.
7) I would guess there are not many words that would be as efficient at doing that.

So let’s propose an answer to the Z13, starting by plugging "The Hippie" into the last 9 spots. Then you would have 4 remaining spots at the beginning of the cipher:

????THEHIPPIE

What could we say about the remaining letters that go in those first 4 spaces?

1) 1 spot must be H, I, P or E. Remember, we must use the same letter from one of the pairs 1 more time.
2) The other 3 cannot be H, I, P, E, or T. But they could be anything else.
3) T cannot be used in any of the 4 slots.
4) The vowels:
– are all available – a, e, i, o, u, or even y – but each one could only be used 1 time.
– More than 1 vowel can be used (ex. Paul), but not I and E together (So, no Reid, for example).

My goal here is to see if there is any way to find a name that works both for the Z13 and the Z408 leftovers. Looking at the Z408 leftovers, there are at least three common names that jump out at you.

Peter/Pete
TImothie/TIm
Robeet (i.e. Robert)/ Rob

We can eliminate Peter/Pete (for this experiment). 1) We need the single P in the leftovers to make "hipie." 2) In the Z13, you could not repeat both the P or the Es. 3) We cannot use the T in the first 4 spaces of the Z13 (It would create a new fifth repeating pair).

We can eliminate Timothy or Tim due to the T (see above).

That leaves Robert. Its short form Rob fits the Z13, and both Rob and Robeet (i.e. Robert) can be found in the Z408 leftovers.
– Robert is obviously too long for the Z13 and has a T.
– Robt, my first thought, fits the Z13 but also has the T problem.
– Converting it to Bob in Z13 would also add a new fifth repeating letter.
– So Rob seems like the closest fit.

ROB?THEHIPPIE

And if you are trying to unscramble the Z408 leftover letters, using Robeet (i.e. Robert) The Hipie leaves you with the letters for "Meet." So the 408 leftovers become the introduction:

Meet Robeet the Hipie

What goes where the last question mark stands in the Z13? Well, we still need to complete the triplet by repeating one of the paired letters from "THEHIPPIE." So H, I, P, or E. I guess it could be I or e to suggest "Robbie." But the RH initials found with the Riverside desktop poem would suggest it’s an H.

ROBHTHEHIPPIE

PS:
I should point out for the Ross Sullivan people …….
ROSSSTHEHIPIE

But it wouldn’t fit the Z408 leftovers.