Reading a bio of Alan Turing : the Enigma (by Andrew Hodges). The guy who broke the Nazi code & invented your computer.

got me wonderin' about the likenesses between:

ring-structure
plot
symmetry/proportion
riddles
labyrinths, mazes
encryption (cipherment/decipherment)
the "abba" rhyme scheme
etc.

John Irwin wrote about (some of) this with great erudition (The Mystery to a Solution : Poe, Borges and the analytic detective story).

So did Alastair Fowler, in his books on number symbolism & structure in Renaissance poetry.