I’m sure that I’m missing many more — as the author puts it — “types of implicit meaning” — in this dialogue, but these are the ones I’ve found so far:

Dialogician’s Acrostic

On page 81, the tortoise says the following:

Most acrostics, however, have only one hidden level — but there is no reason that one couldn’t make a double-decker — an acrostic on top of an acrostic. Or one could make a “contracrostic” — where the initial letters, take in reverse order, form a message. Heavens!

[…]

In the unlikely event that a dialogician should write a contrapuntal acrostic in homage to J. S. Bach, do you suppose it would be more proper for him to acrostically embed his OWN name — or that of Bach?

Now, amusingly, the first letters of the individual pieces of dialogue read as follows:

HOFSTADTER’SCONTRACROSTIPUNCTUSACROSTICALLYBACKWARDSSPELLS’J.S.BACH'

And if we separate the words, we receive:

Hofstadter’s
Contracrostipunctus
Acrostically
Backwards
Spells
J. S. Bach

Which, acrostically and backwards, reads:

JSBACH

With this, Hofstadter has not only embedded both his own name and Bach’s, but he has also created a “double-decker” acrostic in which the second-level acrostic is, in fact, a “contracrostic”.

Which I find utterly delightful.

…

Important

Loose end …