MIT Mystery Hunt 2020/People Mover

People Mover is a puzzle from the round of the 2020 MIT Mystery Hunt.

Solve Path
The puzzle consists of a statement-based logic puzzle and ten square diagrams with numbers on them.

The first thing to do, of course, is to solve the logic puzzle.


 * The logic puzzle will result in ten letters, with stops 3 and 6 being the same letter and everything else being distinct.
 * From clue 3 (Braille), there is exactly one letter between U and Z.
 * Clue 4 states that exactly five letters (including 9) have ascenders in lowercase (BDFHKLT).
 * Clue 6 states that exactly five letters (including 1 and 8) form acute angles in their semaphore representation (AGHOTWZ).
 * Clue 8 states that letters 4 and 7 have a NATO Phonetic Alphabet length of seven (CFJUW).
 * Clue 5 (Morse Code) eliminates H (....), J (.---), and O (---) as options altogether.
 * This leaves only five letters satisfying Clue 6 (AGTWZ). Since Clue 3 states only one of W or Z can appear, one of A, G, or T must be the doubled letter at 3 and 6. This letter cannot be A, as clue 1 states letters 4-7 are in alphabetical order (and no letters come before A).
 * Letter 6 is thus either G or T. Combining clues 2 (after G), 5 (no J), and 8 (one of CFJUW), this forces letter 7 to be the U-Z character, and specifically constrains it to be W. Letter 4 is thus one of C or F.
 * Clue 7 states that letter 10 has the highest Scrabble value. Since letter 7 is a W (value 4), letter 10 must be higher (JKQXZ) but also not J (clue 5) or X or Z (clue 3).
 * However, clue 7 also states that the total score of all the stops is 21. The current letters sum to at least 4 (W) + (1+2+1+1) (AGT+1) + (1+2) (non-T ascenders, at least two since K is still a valid option; here L, D) = 12. This immediately removes Q (value 10) as an option and forces letter 10 to be K.
 * Letter 8 must be one of A, G, or T (clue 6). Clue 5 forces this letter to start with a dot in Morse code (lest it form three consecutive dashes with the W in position 7), so it must be A.
 * Clue 5 also states the Morse code representation has 24 symbols. This is currently at least 3 (W) + 2 (A) + 3 (K) + (3+1+1) (GT+1) + (≥3) (ascender in position 9) + 4 (position 4) + ≥(1+2) (undetermined letters, since E cannot repeat and T already exists) ≥ 23. This forces letters 1, 3, and 6 to be G, T, and T, respectively, since doubling the G would exceed the enforced constraint. It also forces letter 4 to be F, as a C would necessitate another ascender adding at least two symbols to the length.
 * Clue 7's sum is now at least (4+1+5+1+2+1+4) (knowns) + (1+1+1) (undetermined letters) ≥ 21. The three remaining letters must thus have a Scrabble score of 1; this constrains the ascender in position 9 to L.
 * The Morse code representation is also maxed out, forcing one letter with one Morse symbol (E) and one letter with two. By clue 2, the E is barred from position 5 (which must be after F in the alphabet); thus position 2 is E.
 * The Morse code representation is now . Clue 5 says the longest stretch of dots has length 3, which currently does not occur; the only way to cause this to happen is for letter 5 to be I.

The solution to the logic puzzle is thus.

Solving the logic puzzle reveals the phrase. A little bit of MIT knowledge (or a Google search for "getfit walk") reveals a getfit program at MIT that hosts an annual walk in the tunnel system underneath MIT (confirmed by the word "tunnels" in the flavortext).

Solvers must now find the "stops" in the tunnels. Entering the MIT Tunnel system, one can find square plaques with the getfit logo, each one labeled with the letter and including a map directing towards other plaques. Lining these up with the diagrams provided with the puzzle puts a letter at each location with a number, extracting a cluephrase, SHE FELT THE EARTH MOVE, directing towards the answer.