Solve, Index, Sort, Identify - Solution

This puzzle is a play on the Identify, Sort, Index, Solve puzzle type, as coined by Foggy Brume. However, it's all a bit backwards! Instead of an ISIS puzzle, it's a SISI puzzle. On first unlocking the puzzle, teams auto-spent 1 guess on the puzzle's "answer":HERES THE ANSWER TO THE PUZZLE NOW CARRY ON MATE. From here, we must work backwards to the Identify step. This solution presents the steps in order of the puzzle title, but in practice we found solvers jumped between all the steps.

First, we must Solve. This is the given puzzle answer. However, we also need to solve the given clues. Many of the clues are ambiguous as given, but there is hidden structure that resolves the ambiguity: every answer is exactly 10 letters long, and answers are given in reverse-alphabetical order, Z to A.

Next, we must Index. In a normal ISIS puzzle, we are given numbers, and must index them into the words. In this puzzle, we have letters from the answer HERES THE ANSWER TO THE PUZZLE NOW CARRY ON MATE. We must reverse-index these letters to reconstruct the indices that were used. The first letters of the clues spell out a message: GET DIGIT INDICES THEN SORT LAST CLUE WORD Z TO A. Based on the flavortext saying we "start counting from 0", and the length 10 answers, this indicates we should extract digit indices 0 to 9 by 0-indexing into each answer in the given order. This is partially confirmed by trying to reverse-index the Zs from PUZZLE - the given order has LUIGIGARZI and LIZARDKING right next to one another.

After Index, we must Sort. Take the last word in each clue, and reorder the answers based on the reverse-alphabetical order of those words.

Finally, we must Identify. If we read the 1st letters of the answers post-sort, they spell out 5 words: CURVATURE MOLECULES INTEGRAL HELIUM ENTROPY. In an ISIS puzzle, the final step is to recognize a word or phrase out of the generated letters. In this puzzle, the final step is to recognize something out of the generated digits. The digits for each word form famous math and science constants that are associated to each word.

CURVATURE MOLECULES INTEGRAL HELIUM ENTROPY

314159265 602214076 27182818 831446 1380649

These are: π (pi), Avogadro's constant (N_A), e (e), the ideal gas constant (R), and Boltzmann's constant (k_B). Place these into the diagram, and go backwards one last time to get the answer, PINE BARK.

Author's Notes

This puzzle was inspired by two different MIT Mystery Hunts: identify, SORT, index, solve from MIT Mystery Hunt 2016, and the White Queen round from MIT Mystery Hunt 2014. The first step I came up with was identifying famous numbers from digit sequences, and the other mechanics were built backward from there, so you could say I even constructed this puzzle backwards from the final a-ha.

The Solve, Index, and Identify steps never changed, but the Sort step went through several revisions. Puzzlers are very trained to sort as soon as they discover a good sort order, since sorting helps confirm you're doing the Index step correctly. A SISI puzzle needed to be Index-then-Sort, so that convention worked against us. Many of our testsolvers can attest to getting very stuck when they sorted too early and stopped thinking about the original order.

Our first try at fixing this was to have the Sort order rely on the Index order, making it impossible to sort until you found enough indices. This worked, but introduced a new problem: indices got used twice, and there was no checksum to detect 1-indexing vs 0-indexing. Testsolvers would 1-index, spot words from the 1st letters of the answers, and treat that as confirmation of the sort. However, all their indices would be off by one! Recognizing 3-1-4-1-5-9 is reasonable, but error correcting 4-2-5-2-6-10 is too much to ask. The final version of the puzzle changed the Sort to be independent of Index again, with added guide rails to steer away from 1-indexing or sorting first. Making the site auto-spend a guess on the "answer" was a late change, but I thought it was a fun joke that played well with the presentation.

Fun fact: did you know that Google is wrong about some of its constant values? It reports that Boltzmann's constant is 1.38064852 x 10^-23, but in 2019, it was redefined as exactly 1.380649 x 10^-23. It also reports that Avogadro's constant is 6.02214086 x 10^23, when it's really 6.02214076 x 10^23. I understand why no one caught a 1 digit error at the 8th sig fig, but I was still pretty annoyed. Luckily, once you get the constant a-ha the digits aren't too important.