Two literary puzzles I haven't been able to solve:

1. In Nabokov's "Speak, Memory" he writes "We subjected [Uncle Ruka] to a test one day, and in a twinkle he turned the sequence '5.13 24.11 13.16 9.13.5 5.13 24.11' into the opening words of a famous monologue in Shakespeare." The monologue is 'To be or not to be' from Hamlet but the question is whether this was an arbitrary substitution cipher.

Oddly, the first few letters follow the pattern of a rotational cypher where the next letter is x fixed places from the previous (e.g. O(13)=T-5. B(24)=O+13.) but that pattern collapses quickly. It may just be random but I cant get it out of my mind.

2. Borges, in his short-story The Rose of Paracelsus introduces the name Johannes Grisebach out of nowhere! Who is Grisebach? There was an Eduard Grisebach, a poet and the editor of the works of Schopenhauer who was known to Borges.