Solution: Computer Science Meta
Answer: PEST CONTROL ASSAULT COMPLETE
Written by Amos Eshel
This is a very weird round. Puzzles need to each be solved multiple times, and the solutions to these puzzles need to be used in other puzzles. The meta, on the other hand, is comparatively simple: solve each puzzle with a new input word provided directly (and newly appearing as an option in the submission system), and then recurse one time, and feed those answers into one of the other puzzles, provided with some bad ASCII art.
Retranslating the arrows leads to the left side here:
LOGIC(EMPTY(pawn)) = LOGIC(UPON) = CONTROL
EMPTY(CLUES(lock)) = EMPTY(SALT) = ASSAULT
LIST(LOGIC(quayd)) = LIST(CORD) = COMPLETE
Author’s Notes
I have been planning to write another Catch-22-like round since finishing that original 8ish years ago. I always called it Catch-23, so luckily I was able to write this for Puzzlehunt 23. The function call, input/output nature came about from some conversations with Jonah. I knew there’d be another blank puzzle that had to be backsolved, but the exact mechanics waited till there was a meta pun; at which point SALT → ASSAULT jumped out at me. A mastermind-based puzzle (CLUES) and a puzzle with a grid-based set of changing words (LIST) were two of the original ideas I had for Catch-23, and translated well with the switch to function calls (unlike a number of other ideas that will now have to wait for Catch-24).
I’m pleased with the weirdness that is this round, though a little saddened that in the end it doesn’t have quite the same Catch-22 feel of needing to solve puzzles in at least pairs. While there are a number of different ways through Computer Science, LIST had to provide perfect backsolve information for its EMPTY & LOGIC feeders and can ignore its CLUES feeder (though this is also backsolvable by clever/persistent teams). Meanwhile LOGIC cannot have much progress made before its feeders are better known. CLUES on the other hand can generally be solved sans most of its feeders if all the cryptic clues are known.
[If you haven’t seen Catch-22 and are interested you can email me at eshelamos at gmail. Catch-22 is a module (aka round) from Microsoft Puzzlehunt 16 and the archives are unfortunately not accessible to the public.]