acrostic v steganography
There are some who insist the characters found on the back cover of the Rubaiyat are an acrostic.
a poem, word puzzle, or other composition in which certain letters in each line form a word or words.
There are others who hold that the characters found on the back cover of the Rubaiyat are examples of steganography.
the practice of concealing messages or information within other non-secret text or data.
This doesn’t mean the acrostic folk disbelieve in the existence of steganography, they just don’t believe it applies in the Tamam Shud case.
The luxury of such a negative conclusion is that no reasoning is required to support it, other than a personal bias.
As an aside, imagine the frightening concept where both the Tamam Shud code and the Voynich Manuscript are proved to be examples of steganography.