1996 MIT Mystery Hunt Solutions

Shortly after the 2012 MIT Mystery Hunt, the main Hunt site was redone quite nicely, and some additional Hunts (sans solutions) were added into the archives. This of course presents a kind of challenge, and some of the most devoted members of Beginner's Luck took up that challenge. The results of our work are presented below. (Updated in 2023 after some of the missing information was found.)

Two of us both had the Vintage Books edition, September 1980 printing of Gödel, Escher, Bach, a version that would have been available to solvers and was likely to be the one they used. We don't know if there are other editions with different pagination, but this one worked. All page number references below are to that edition.

Puzzle 1A

No matter what integer is plugged into the formula, taking it modulo 360 gives the answer 29.

Puzzle 1B

The graphic and answer for this puzzle were previously posted on the Hunt web site. The answer is SHOEPRINT.

Puzzle 1C

Starting at the upper end of the string, break the string into trigrams and translate them into amino acids. Then solve the result as a cryptogram. (Some of the letters use the familiar single-letter abbreviations for amino acids, but others are different. Perhaps there was another code in use in the past or perhaps they just made acids stand for their initial letter when possible, without using any established code.) It decodes to:
The beginning and end are junk, but the middle is an instruction referring to the Aria with Diverse Variations that appears beginning on page 391 of GEB. If you just jump to the end of the text on page 405, you will not find the answer. But if you actually read the Aria, you will see that on pages 402-403 the characters discuss the subject of making the reader have to search for the end of a text by putting some red herring content after the actual end. There are several clues, but most notably the missing letters in Tortoise's last speech on page 404 tell you that this speech is the actual end of the Aria, and the knock and the following part is not really part of the story. So the answer is found in that speech, and it is SWEET DREAMS.

Puzzle 2A

Extend the lines through the shapes laid over them, and in each small shape will appear an intersection of lines which forms a letter shape. The letters spell LEAFY LAKE.

Puzzle 2B

The game played here is equivalent to a game called Bogus Nim. You can find references to it online, though at the time of the hunt, solvers would have had to find a book such as the one cited in the flavor text. Summary of the strategy:

Each legal move either adds chips into or removes chips from pile B or pile D. Treat each game as a 2-heap nim game with these heaps, ignoring the others. The game is called bogus because chips can sometimes be added to a pile instead of removed from it. But after the second player makes any such move, the first player can return to an equivalent state by removing those same chips; the first player never needs to do so. Because there is a finite supply of chips to the left of these piles, there is a finite number of moves which add chips available, and so it is effectively just regular nim.

Two-heap nim is easy: You just make the piles the same size. So you win by moving 2 chips out of D, 8 chips out of D, 6 chips out of D, 21 chips out of D, and 5 chips out of B. Concatenate these per the instructions, and write with a comma as suggested by the example, to get the answer 286,215.

Puzzle 2C

Part of this puzzle is segment #3 of the audio tape, listed on the program as 8:10: Ornithography: Tweety Bird and Friends.

This puzzle is an audio cryptogram. Each bird call represents a different letter, and there are gaps between words. (There is an error in the audio: the gap between the first two words is missing). The page in the puzzle packet contains 20 clusters of bird footprints, and they correspond to words. Two bird feet = 1 bird call = 1 letter. So the lengths are 2, 5, 2, 3, 8, 3, 5, 4, 6, 3, 1, 6, 3, 1, 6, 3, 1, 6, 3, 4. The words start at approximately these offsets in the audio track: 0:00, 0:08, 0:28, 0:37, 0:51, 1:20, 1:34, 1:55, 2:11, 2:32, 2:46, 2:53, 3:15, 3:27, 3:33, 3:54, 4:06. (Another error in the puzzle: There are too many sets of bird prints on the printed page. The sequence 6, 3, 1 repeats one time too many.) The noice starting at 4:20 appears to separate he audio tracks


Puzzle 3A

The 9-letter Boggle words are ADJECTIVE, GENUFLECT, SECRETARY, RIGMAROLE, LUDICROUS, ZESTFULLY, EMPHYSEMA, SYNDICATE, and CIRCUITRY. Per the instructions, you find that the consonants that appear exactly three times among the unused letters are D, H, P, R, S, and T, and the vowels which appear exactly 6 times among the unused letters are E and O. The only anagram of these letters is POTSHERD.

Puzzle 3B

Part of this puzzle is on the audio tape. It's segment #1 listed in the program as 8:00: Lifestyles of the Rich and Famous: The Millennium's Top Sixteen Symphonic Highlights. The handout tells us to list the composers in chronological order as to when the music was composed (with a note that two of the pieces are ambiguous, but to use the date of first performance of the second piece, the publication date of the third). Then extract these letters from the composers: 5 3 2 1 1 2 7 2 2 3 4 2 7 3 6 8. A solving team got the answer ENIGMA VARIATIONS. In the order they appear on the tape, the compositions are

  1. Ride of the Valkyries, part of the opera The Valkyrie by WAGNER (1851-1856).
  2. Pachelbel's Canon in D Major by PACHELBEL (1680-1706).
  3. Appalachian Spring by COPLAND (1943-1944)
  4. Water Music Suite No. 2 in D Major by HANDEL (1717)
  5. Surprise Symphony by HAYDN (1791-1792)
  6. The Marriage of Figaro by MOZART (1786)
  7. Rhapsody in Blue by GERSHWIN (1924)
  8. Symphony No. 2 (Op. 73) by BRAHMS (1877)
  9. Symphony No. 5 in D minor (Op. 47) by SHOSTAKOVICH (1937)
  10. Pastoral Symphony (No. 6) by BEETHOVEN (1808)
  11. Spring (Concerto No. 1 from The Four Seasons) by VIVALDI (1718-1720)
  12. (unsolved number 12)
  13. Symphony No. 6 (Pathetique) by TCHAIKOVSKY (1893)
  14. Adventure on Earth (from E.T.) by WILLIAMS (1982)
  15. (unsolved number 15)
  16. Carnival of the Animals by SAINT-SAENS (1886)

I couldn't identify two of them. Per the hint sheet, one of them is Gluck, who lived in the 1700s and has to be between Vivaldi and Haydn. This gives us PACH(E)LBEL HA(N)DEL V(I)VALDI (G)LUCK (M)OZART H(A)YDN BEETHO(V)EN W(A)GNER B(R)AHMS SA(I)NT-SAENS TCH(A)IKOVSKY (Someone with 2nd letter T) GERSHW(I)N SH(O)STAKOVICH COPLA(N)D WILLIAM(S) to spell ENIGMA VARIATIONS.

Puzzle 3C

The two-letter codes are the first two letters of the first 14 distinct names (ignoring initial numbers) of the books in the Protestant Bible: Genesis, Exodus, Leviticus, Numbers, Deuteronomy, Joshua, Judges, Ruth, Samuel, Kings, Chronicles, Ezra, Nehemiah, and Esther. If you stack the cards in this order, with the unlabeled card on the bottom, then a card with letters appears as every 3rd card, and reading through the holes leads to exactly one letter on each card:
It's not particularly obvious from this, but the answer is UNMON, the name of a Zen Master who appears on page 254 of GEB. (The puzzle text says the answer will be a person's name.)

Puzzle 4A

This puzzle is on the tape. It's segment #4, listed in the program as 8:14, Soundstage Presents Moxy Früvous. It's a complete recording of "The Drinking Song" by Moxy Fruvous, so it sounds similar to this. The lyrics match these to the word. There's also sheet music for it, matching the statement in the puzzle that the song is in G (because I have neither the musical ear nor the patience to transcribe all those notes). But following the directions to write down all "spellsung" words whose spelling matches at least one of the notes it's sung on (even if a different syllable is sung there), we get this list:


The sheet music also has the right lyrics. In compiling the list, I took "good night" to be two words (the linked lyrics site has it as one) and corrected the spelling of campaign in the sheet music (missing the G, which is the note it hit).

Now we have to delete any group of three words where the first is the same as the last (which is none of them, unless we take goodnight as a solid word, in which case all three goodnights are on the list and they get removed). Then for each repeated word, delete all occurrences except the first. That gets rid of the repettions of the chorus, A, PLAYED, GOOD, NIGHT, AND, and FLYING. We reverse RECORDS and AROUND. To make it work, I had to assume one other spellsung word from the chorus, and one before NOTICE, which I've marked as [missing]. I also had to assume that we do delete all the GOODNIGHTS. The final word list is:


Then we take the last letters of words 7, 15, 24, 33, 38, 48, which are A STOOD NOTICE BONES CANNOT AMBULANCE to give ADESTE, and the first letters of 35, 32, 25, 19, 18, 12, 8. These are FLYING IMPOTENT DRINKING'S ESIAHC LIKE EMOS SOLID to give FIDELES. The answer is ADESTE FIDELES.

Puzzle 4B

The trip-lets, clockwise starting from the top, contain the letter groups TNN, OHT, VIE, SNE, SRC, BEE. Reading one letter from each group in this order, cycling around until all the letters are used, spells "This sentence no verb" which appears on page 495 of GEB. Following the directions below the puzzle on this page leads to the answer FLOATING CASTLE.

Puzzle 4C

The number sequence is 0 9 18 3 12 21 6 15 24 1 10 19 4 13 22 7 16 25 2 11 20 5. This can be interpreted as the results of numbering the cells in a 3x3x3 cube from 0 to 26, then reading out those numbers using a different ordering of the dimensions, and with the last 5 numbers missing. This assigns A through H the values 9, 21, 6, 15, 19, 13, 22, and 25.

Then match the numbers with pieces, rotating them so that the intended numbers are upright. Each number appears on only one piece and exactly one of the numbers appears on each piece. The spaces between the pieces spell ESREVER, which is REVERSE spelled backwards. For the second part of the answer, just plug the numbers into the formula to get 723.

Puzzle 5A

This puzzle is on the tape. It's segment #2, listed in the program as 8:07: Language Lessons: Parlez Zee Ruskie? As expected, it's people speaking in various langauges. It probably gives one word from what each speaker is saying in a different language. The hint sheet tells us the languages are French, German, Russian, Dutch, Hakka, Thai, Arabic, and Persian. A solving team got AND CAN IT BE THAT I SHOULD GAIN.

Puzzle 5B

Solve the crossword.

Clue 11 down and its answer tell you that you need to fold the puzzle into a tetrahedron. Edge letters that extended beyond the boundaries implied by the dashed lines get cut or folded away. Clue 24 across and its answer tell you that you need to look for answers crossing the edges in the final puzzle. There are three edges that come together to form the tetrahedron (as opposed to simply being folded) and on each one, there is just one space where two squares with the same letter in them meet at the edge. Reading the entries through those spaces yields EDGERTON ROOM NUMBER. There are several places at MIT named Edgerton, but we believe the intended answer was 4-405.

Puzzle 5C

It should be fairly clear that Achilles and the Tortoise are performing a series of transformations on some string of characters. But what string? The Tortoise helpfully suggest you should "start with a complete list of problems", and the text of this puzzle contains several misspelled words: compliment, monsterous, surprize, capitol, congradulations, disfunctional, embarassed, and affect. Concatenating them (without correcting them) gives:


Now remove every other letter, starting with the first:


For every string of all consonants or all vowels of length greater than two, remove all but the first two:


Replace both instances of PIE with CAKE:


Remove all three instances of OS:


Remove the reversed CUE:


Remove the conjunction IF:


Twenty letters remain. Take the last five, reverse them, and move them after the tenth letter:


Change all Rs to Ls and all Ns to Ts:


Remove TAKE:


The FA of "fad" appears in the string; replace it with the D:


Remove CC:


Change the first A to an R, and remove the other A:


And reverse the first two characters, along with the whole second half of the string:


CORKED BOTTLE is the answer.

Puzzle 6A

It doesn't take long to prove that the problem is unsolvable in base 10. χ can't possibly be both small enough to produce a number smaller than 80 in the third multiplication and large enough to produce three-digit numbers with two distinct first digits in the other multiplications. Given that we only have eight distinct letters to work with, base 8 seems worth a try, and sure enough a unique solution falls out:
Now the letters off to the side translate to 467, 103. This needs to be converted back to base 10 to get the correct answer, 311,67.

Puzzle 6B

This puzzle is on the tape. It's segment #6, listed in the program as 8:30: Wild Kingdom: The Beaver's Natural Habitat. (But note that there is no track 5; that's the silence at the end of side 1 of the tape.) It's an ambient noise runaround of MIT featuring footsteps, traffic noise, etc. At various points, the first at 3:15, there is a voice pointing out some word on a sign and asking you to take a specific letter in it. It might not be solvable today but I would love to hear about it if anybody tries! A solving team got THE MUSIC OF THE NIGHT.

Puzzle 6C

The path is:
A right
R up
I left
E up
T right
T right
G down
I left
E left
T up
T right
E down
T left
A down
R right
M right
I down
T left
A left
R down
Applying the shifts as instructed yields DSITEPJBIVALVEXMBNET. The clear longest word is BIVALVE.

Puzzle 7A

To solve this puzzle, write the alphabet above the pangram:
Use this as a cipher key, decoding J, the number above 1 in the example, once by finding the letter below where J appears in the alphabet, which is P. Do the same for N, which appears above 2, but do it twice, decoding N to B and B to U. Continuing in this way yields PUZZLERS. Doing the same for the second set yields HAUSSMANN, the answer.

Puzzle 7B

  1. We did not go hunting for the illustration which may or may not still be available in Samuel Adams park. The hint sheet says it is on the side of the park nearest the Holocaust Memorial, and another announcement says this is for real. It's part of a work of public art, a long line in the pavement that shows the original Boston Harbor shoreline from the 1600s before the city started filling in the harbor to make more land. Most of the art in this line shows seaweed, shells, and other shoreline objects, but they managed to get an illustration from GEB included.
  2. We backsolved this answer first, but upon seeing it was a six-letter answer, so the first word needed to be four letters, we determined the correct illustration is the neuron on page 339, which contains word A, GLIA, which is the anagram of Gila, the name of a monster.
  3. The first acronym after glia in the index is GOD which it specifically says is an acronym. Its last page number, (a), is 722. This is in the Six-Part Ricercar where they are making up alternate titles for GEB, and the second such title is Giraffes, Elephants, Baboons: an Equatorial Grasslands Beauty, so the third initial is B. Replace the A in GLIA with a B to spell GLIB.
  4. The first word of the first title on page 722 is Copper. The only page listed in the index for copper is (b), page 173. The text describes a picture made of dots (forming the Fibonacci sequence) and says a colon after the word "another" is an example of this picture with 2 rows. So the fifth letter before the "picture" is an O, which replaces the I to spell GLOB.
  5. The third numeral on page 173 is 2, and the sixth is 8 (again from the Fibonacci sequence). So (c) is 2+8 = 10 and we go to the 10th listing in the index, acoustics, on pages 7 and 81, so (d) is 81. The first letter on page 81 is an E. Now e have GLOBE.
  6. "Would" appears about halfway down page 81 after the word "it", so alpha is a T. The last T entry in the index is "typos" on page (e) 404. In the Tortoise's last speech here, which is (per comments earlier in this dialogue) the real end of the dialogue, three letters are omitted from words, spelling END, to signal that this is the real end. The D is missing from "Golbach", so we remove the G.
  7. The first name in the the list on page 404 (beta) is De Morgan. The 30th entry before De Morgan in the index is "cows" and its third page number, (f), is 351. The first two-digti number on page 351 is 18. The 18th letter of the alphabet is R. We can replace either the L to get ROBE or the B to get LORE.
  8. The last letter in the last paragraph on page 351 is Y. The first index entry starting with Y is yes-answers. The first page referenced there is (g) 461. The first letter on page 461 is B. Presumably we aren't meant to go back to LOBE or replace a B with a B, so the most reasonable result is that word F is LORE and word G is BORE.
  9. If the Tortoise counts as a person, then the fourth person mentioned on page 461 is Augustus, King of Saxony. His index entry is on the opposite side of the page from the index entry for "and", and three below this is (gamma) "anomalies". The forth page for that is (h) 435. A bit below the middle of the page we find "A king without a subject would be -- an anomaly, of course." The subject of the sentence is "king" and the letter preceding it is A, so we replace the O with an A to get BARE.
  10. Thie historical figure discussed on page 435 is Willard Van Orman Quine. Reverse the letters in his surname to get ENIUQ which is listed as ENIUQ (procedure) in the index.The 41st following index entry (delta) is fermatas, whose first page is 275. A fermata is a pause (and is unrelated to Pierre de Fermat, who is also mentioned on page 275). The last pause is in Achilles' penultimate speech, "Pauses for a moment to sip his tea, then resumes." So the first letter is P. The word immediately above it is "provoked" and its sixth letter, (epsilon) is K. Replace the R with a K to get BAKE.
  11. The seventh index entry starting with K, (phi), is kitchen sink, and its only page (i) is 315. Kitchen sink appears about 1/3 the way down the page and the next proper noun is the name of the next character to speak, Anteater. Its last letter is R, so we get BAKER.
  12. The person discussed on pahe 315 (not the noun used in the last step) is Aunt Hillary, and the index entry mirroring hers on the opposite page is "chunking". The preceding index entry (lambda) is "chunked versions of this book" and the first location listed is jacket. The phrase after the colon on the jacket is "An Eternal Golden Braid". The most frequent consonant in this phrase is N, which gives us BANKER.
  13. The last page listed for chunked versions of this book is (j) 777. Page j-10, or 767, is in the index, and (mu), the last phrase in quotes on this page, is "last step" and its last page (k) is 468. "Last step" occurs near the end of the first paragraph, and the letter immediately following is the N in "necessary". Replace the K with and N to get BANNER, the final answer.

Puzzle 7C

The columns, decrypted:
The properly assembled inventions, and their inventors:
Enter these names into the grid as shown:
MOZART'S FORTIETH is the answer.

Puzzle 8A

The pattern you have to figure out is that each group of 3 of more letters which contain a stroke running in the same direction (vertical, horizontal, or either of two diagonals) that the letters run in is circled.
The highlighted letters above are the ones not in any such group. They spell CONSTRUCTION WORKERS.

Puzzle 8B

A little experimentation will lead to multiple solutions ending on white's 8th move, so a shorter solution is needed. That solution is:
White from to Black from to
a4 7 5 c6 18 19
a5 5 4 Qb6 25 11
a5xQb6 4 11 Kd8 33 25
b6xa7 11 2 Kc7 25 18
a7xNb8=R 2 9 RxRa1 1 8
The sums of the from and to spaces, respectively, are 131 and 112.

Puzzle 8C

This is a phonetic crossword puzzle. You have to enter one phoneme in each square.
b ɛ s t

d ʌ m

ʌ p s
æ l t o

r u l o
ʌ g ər ʌ
s k u p s
ɪ r o d
t o l d

ɛ k s
h ʌ v ər

m ʌ d
s i k
ɒ m i
k l
u d o
ʌ w

ʌ s w d͡ʒ
s u n ɒ m i

w ɪ n d

t i

v i l

æ k t ər

l æ p t ɒ p
k w ɪ z d

w n
ɪ n ər
s ɒ d
ɔ r ʌ
i z D
h ər s

f r i d
k ər ʌ

d o m ʌ
t r l
l ʌ ʃ l i
k ɒ n
r ɛ d i

p r u v
n ʌ b

s i

t i m z
The answer is spelled phonetically along the bolded diagonal: BLUE SUEDE SHOES.

Puzzle 9A

We didn't solve this puzzle. But we backsolved the answer CLOTHESPIN which has to belong to either this puzzle or 9B. Alex Fink pointed out after this was first posted that this answer should go to 9A since it causes the threads of puzzles to be "braided" through the 12 rounds, with a repeating ABCCBA pattern.

Puzzle 9B

This puzzle is based on the string which we don't have. But I've been told that the comment in the flavor text about drinks was a clue that you needed to wrap the string around a soda can to line up the markings on it properly to read the answer. Photos (1) (2) (3) from the team that solved this show the answer HONESTY.

Puzzle 9C

Postal bar codes encode 12 digits using a 2-of-5 code: Each digit is encoded by five bars, two of which are tall. The first and last bars are always tall and are not part of any digit. The first nine digits encode the 9-digit ZIP+4. The next two digits provide the last two digits of the street address. The final digit is a checksum such that the sum of all 12 digits is a multiple of 10.

Each of the zip codes leads to a university, but for some of them, the checksum is wrong. Those wrong checksums are struck out below:

Skipping the invalid barcodes, read the first letter of the first school, the second letter of the second school, etc. as instructed, and shift each letter back one position in the alphabet (which is done on page 404 of GEB as an imitation of Cantor's diagonal proof that the real numbers are uncountable) to get HARTLEY ROGERS.

For the second part of the answer, Oberlin, Haverford, and Kalamazoo were all founded in 1833. The youngest school is Hawaii Pacific which was founded in 1965, so was 31 years old at the time of the Hunt. The oldest school was Columbia, founded in 1754, 242 years old at the time of the Hunt. Dartmouth and Brown were also founded before 1800. Perform the calculations specified to get 476.

Puzzle 10A

This web-based puzzle and its solution are already on the web site, and the answer is SOMEWHERE OVER THE RAINBOW.

Puzzle 10B

The solution to the domino puzzle is:
1 0 0-6 5 6-4 5
| |     |     |
1 2 2-1 3 3-4 2

3 0 3-1 4-5 6-6
| |
3 1 6 0-0 2-4 6
    |         |
2-2 5 5 6 2 4 1
      | | | |
4 5-0 1 3 3 0 2
|             |
4 3-0 5-5 4-1 6
The letters corresponding to horizontal dominoes spell RIND ON THE WALL.

Puzzle 10C

The puzzle is based on the Qwerty typewriter keyboard. Each letter is either the correct one or one of the two letters adjacent to it in the same row of the keyboard. All spaces and punctuation are correct. It decodes to the following paragraph, a more detailed version of the anecdote from page 565 of GEB; this version is from The Man Who Knew Infinity, a biography of Ramanujan published in 1991.
"I was talking the other day," said William Rogers to the other villagers gathered around the inn fire, "to a gentleman about the place called Louvain, what the Germans have burnt down. He said he knowed it well...used to visit a Belgian friend there. He said the house of his friend was in a long street, numbered on this side one, two, three, and so on, and that all the numbers on one side of him added up exactly the same as all the numbers on the other side of him. Funny thing that! He said he knew there was more than fifty houses on that side of the street, but not so many as five hundred. I made mention of the matter to our person, and he took a pencil and worked out the number of the house where the Belgian lived. I don't know how he done it." Perhaps the reader may like to discover the number of that house.
The answer to this puzzle is simply the answer to the math problem (the one which fits between the limits of 50 and 500), which is 204.

Puzzle 11A

The solution to the cryptic crossword is:
The songs are from the 1890s. The letters in the shaded squares spell the answer TRY TO REMEMBER. Clue answers:

Across: 1. song. 10. EYESIGHT - EIGHT. 11. RE(CAFE)D rev. 12. song. 13. dbl. def. 14. EDITOR IS anag. 16. song. 19. hidden: abroAD A Romantic. 20. RUIN MY anag. 22. HOY rev. + O. 26. BEG ALMS anag. 28. song. 29. hidden: tEXAn. 30. EASTER anag. 31. LOVER (L moved to end) + IE. 32. song. Down: 1. TRI(B)AL 2. DADDY -DY + ED? 3. HAMFATTER anag. 4. LIAR rev. 5. AS INCHES anag. 6. O + RIB + I. 7. M OR N (m and n are both abbreviations for noon, m from the Latin meridies). 8. song. 9. A + MEN. 12. song. 15. LOOT rev. 17. D + ANGORA - ORA. 18. song. 21. I'M rev. + A + OW. 23. HE(X)ED. 24. hidden: hasTY ROmeo. 25. hidden: bunGLE Every. 27. A RAM rev. 28. M + AM.

Puzzle 11B

After selecting the 9 spaces indicated, there are only 2^16 ways for mines to lie ignoring all the other clues. These can be easily programmatically examined (even by 1996 computing standards) to calculate the clue numbers each one would yield, discarding any sets where the clue numbers violate the given clues (any 0s, more than 2 of a number, or fewer than 3 solutions). Out of the remaining solutions, the clue numbers 121463342 are found to have two or more solutions with each of 9 mines, 10 mines, and 11 mines, and thus none of these can be the number of mines. Clues 122464353 lead to multiple solutions with 12 mines and one with 13, and no other case (save for this case's rotations and reflections) works with any number of mines less than 9 or more than 12. This turns out to be the correct orientation to satisfy the B1 not a mine clue, yielding the board:
1 2@2
@ @ @
After performing the indicated calculation and writing the result in base 36, the answer is 757MSSRS.

Puzzle 11C

1 is ^, 2 is <, 3 is /, 4 is \, 5 is >, 6 is V. This yields the path:

And the letters corresponding to the indicated steps translate to ECHECS, the French name for chess.

Puzzle 12A

The number sequence consists of the dates of Easter from 1996 to 2036, written with the month and day number concatenated. The missing numbers are 325,413.

Puzzle 12B

It's unclear at first what form should answers should take, especially people's names. It's a great help to notice that there are twenty-six questions, which, along with the presence of easily-gettable, unambiguous answers starting with Q and X, should make solvers suspect there'll be one answer starting with each letter of the alphabet.
  2. RODGERS [to create "Oklahoma!" and "Carousel," respectively]
  3. LAREDO ["The Streets of Laredo" borrows its melody.]
  4. BEETHOVEN [Eroica]
  6. PIERSON (Music for Orchestra)
  7. WEILL [The Three-Penny Opera]
  8. MUSES (formally MIT Muses, but they already gave us the "MIT")
  11. JEFFERSON AIRPLANE ["White Rabbit"]
  12. ?
  14. NIPPER
  15. ?
  20. GEORGIA [Columbus, GA is smaller than Columbus, OH; Arlington, VA (not actually a city and smaller than Columbus GA) is the only other example among the top 100 cities by population in the 1990 US census]
  23. ?
  24. ATHENS, GREECE [backsolved]
Time has made some of the questions more difficult to research, but it's clear from what we have that the answer is THEME FROM DEEP SPACE NINE.

Puzzle 12C

With a little work it is possible to determine that the previous Life generation to the one shown was:
Forming the answer DINING.

The Impossible Tribar

The last part of the packet consists of 14 pages containing three meta-puzzles. Each of the descriptions of these puzzles clearly states it takes 13 answers as input, but we have only 36 apparent puzzles. However, each of these 14 pages has a letter string at the bottom which is unrelated to that meta.

These strings should all be considered together as an additional puzzle. The similarity of these strings across the different metas should clue solvers in to their relevance. Letter frequencies and some similarities in some of the strings (especially near the beginning and end of string 7, and between the last two strings) can help to determine the encoding used here.

Within each string, starting with the first letter, read every third letter, wrapping around until all letters are used, and then continue with the next string. With normal punctuation, spacing, and capitalization added, this reads:

Congratulations, you have discovered the impossible tribar.

The smallest room number in the 3rd passageway of one of the trails is one of the clues for one of the other trails.

On this latter trail you should take the 1st serial number, divide it by 49 and take the remainder. Do the same with the 2nd serial number except with 61 instead of 49. Do the same with the 3rd number except with 89, with the 4th number except with 53, with the 5th number except with 91, and with the 6th number except with 64. This will give you 6 numbers that you should convert to letters to spell out a clue for the remaining trail.

On this final trail obtain the clue for the 1st trail mentioned above by using the right hand column when you reach the Boston Edison Company. Take row 3 letter 5, row 1 letter 26, row 2 letter 3, row 4 letter 7, row 5 letter 8, row 7 letter 1, row 6 letter 13, and row 5 letter 2.

The first trail mentioned is clearly the last one in the packet, the Bach meta, based on a partial map of MIT. The answer it provides will be a room number, which works as an answer into the Gödel meta. (This was backsolved to be 6-207.) This is the second trail mentioned, which uses serial numbers from fire equipment around MIT. Based on a backsolve of the Escher meta, the word it gives is SYZYGY. The last trail is from the Escher meta. One of the instructions in that trail specifically sends you to the Boston Edison Company (a piece of equipment with their name on it) where we followed the extraction directions to get ODE TO JOY.

Gödel meta

In each numbered set of three puzzles, one of the answers can be interpreted as a reference to some text within GEB, providing the key mentioned in the last bit of instructions. These answers can be specific text located in the book via the index, a page number (starting at the beginning of the page), a page number and a word found on the page (starting at the word), or a page number and a word number, requiring you to count words on that page to find the starting point (up to 413 words in one case). The key strings count ALL letters and numbers that appear starting at this point, including footers and page numbers before crossing to the next page when necessary. Fortunately, the answers are applied in order to the given strings:
Puzzle Answer Starting point for key Start of key text
1A 29 Beginning of page 29 Three-Part Invention Achilles (a Greek warrior
2B 286,215 Page 286, word 215 left the game strategically almost the same
3C Unmon Just after Unmon in the heading on page 254 If words are bad and thinking is bad
4C reverse, 723 The word reverse on page 723 reverse order? A few words were changed
5B 4-405 Page 4, word 405 much, that he resolved to buy them all up.
6A 311, 67 Page 311, word 67 question is staring us all in the face
7A Haussmann The name Haussmann in the photo credit on page 2 Haussmann Introduction: A Musico-Logical Offering
8B 131, 112 Page 131, word 112 end in order to avoid the mental effort of keeping track
9C Hartley Rogers, 476 The name Hartley Rogers on page 476 Hartley Rogers' book, to explain. But the intuitive idea
10C 204 Start of page 204 CHAPTER VIII Typographical Number Theory The Crab Canon
11B 757MSSRS The abbreviation Mssrs. on page 757 Mssrs. C. H. O. Trevelyan from Sara Turing
12A 325, 413 Page 325, word 413 of all the neurons, and all the interconnections
Tribar 6-207 Page 6, word 207 carried out as well as possible, and it has
The last one of these was backsolved by partial brute force after reducing the scope of possible answers. We knew from the tribar that the answer needed here was an MIT room number which was the smallest in one of the corridors on the Bach map, which only covers buildings 1 through 8 and 10. We used the start of every word in the first ten pages of GEB (which thankfully include three pages with little text) as a potential key, and decoded the first line of 56 characters for each. A function scored each of these by how English-like it was: ETAOIN SHRDLU scored 2 points each, other letters 1, and digits 0. The best score by this function by a wide margin was the correct decoding.

Decoding the Instructions

All the key texts have been found, and all of the messages have been decoded. These are (with capitalization, punctuation, and spacing added):
  1. This trail consists of ten checkpoints which you must visit in order. Each checkpoint consists of an MIT room plus a piece of fire equipment in or on one of the walls of the corridor just outside the room. The white serial number on the blue number plate associated with the piece of fire equipment at a checkpoint specifies, according to the rules given below, the building number of the next checkpoint on the trail. The rules below also tell you the room numbers of the checkpoints and the order in which the rooms must be visited. By a room number, we mean that the building number is excluded, e.g., the room number of 26-100 is 100. The first building number is 2. When you are done, plug the ten serial numbers into the formula for the final answer.
  2. The 3rd digit of the current serial number equals the twelves digit of the building number of the next checkpoint, when said building number is written in base twelve.
  3. Room 282 should be visited immediately after room 321e.
  4. Between your trips to rooms 365 and 034, not necessarily in that order, you should make trips to three other rooms.
  5. Immediately after visiting room 034, head for room 001. Visit room 562 before room 282 but not necessarily immediately before.
  6. Go to room 551 immediately before going to room 207.
  7. Be sure to visit room 365 immediately before room 044.
  8. The fifth digit of the current serial number plus the building number of the next checkpoint is divisible by three.
  9. Take the difference between the sixth digit of the current serial number and the building number of the next checkpoint. This difference will be divisible by four.
  10. You should go to room 207 exactly five checkpoints after room 023.
  11. After, but not necessarily right after visiting room 001, visit room 321e. Stop by room 044 right before room 023.
  12. Visit room 562 before room 551, but not necessarily immediately before.
  13. Add an E to the front of any building number containing a 5. If the third and fourth digits of the current serial number are 20, then the piece of fire equipment associated with the next checkpoint is a fire extinguisher; otherwise, it is a firehose.

Runaround Reconstruction

Clues 1, 2, 8, 9, and 13, taken together, tell you how to find the building numbers, described concisely as follows: The first building number is 2. If the third digit of the serial number you find near one room is c, the fifth digit is e, and the sixth digit is f, the next checkpoint is in building 12c + (8e+9f)%12, where % is the modulo operator. If the building number contains a 5, add an E in front of it. Additionally, clue 13 tells us to look for a fire extinguisher whenever our previous serial number has 20 as the third and fourth digits, and a fire hose otherwise.

The other clues tell us all the room numbers and the order to visit them. Two of these provide two separate clues which I have labeled a and b in the logic that follows.

Clues 3, 5a, 6, 7, and 11b give us several pairs of rooms that must be visited consecutively and in order: 321e-282, 034-001, 551-207, 365-044, 044-023. The last two pairs obviously combine into a single block of 3.

Clue 10 tells us 207 is exactly five checkpoints after 023, so this gives us the block 365-044-023-?-?-?-551-207.

Clue 4 tells us to visit three other rooms between 365 and 034, not necessarily in that order, which gives us one of the following two groupings: 034-001-?-?-365-044-023-?-?-?-551-207 or 365-044-023-?-034-001-551-207. The first of these is impossible because it is longer than 10 checkpoints.

We have the following additional clues which tell us to visit two rooms in a particular order, but not necessarily consecutively: Clue 5b: 562 before 282. Clue 11a: 001 before 321e. Clue 12: 562 before 551. Clue 11a forces the 321e-282 pair to come at the end of the sequence (immediately after 207, or else the sequence is too long). Then either of the other two clues is sufficient to place the remaining room (just by telling us that that room is 562, but for confirmation, both clues are correct) So the room sequence is 365-044-023-562-034-001-551-207-321e-282.

We attempted to perform this runaround. At 2-365 we found serial number 752512, which sends us to building 26. At 26-044, we found serial number 750996, which sends us to building 6. At 6-023, the closest serial numbers are 730506 and 730641, which would send us to buildings 6 and 5, respectively. The first two of these serial numbers match the first two letters of the backsolved answer SYZYGY which we got from the Escher meta, using the procedure described in the tribar solution. But neither of these serial numbers in building 6 works for the next letter (which should give us a serial number which is 26 modulo 89), so we think they are both wrong. There was a significant remodeling of building 6 which was completed in 2007, and we fear that this has caused the replacement or relocation of the fire equipment originally located near this room.

It may be possible to pick up the trail given that the next room number is 562, and most MIT buildings either do not have a 5th floor or do not have enough rooms on the fifth floor to number up to 562. It may even be possible then, given the third digit of the serial number, the last two digits each limited to 3 or 4 possibilities, that the number is six digits beginning with a 7 (at least, all the ones I have seen are), and that it must be 26 modulo 89, to backsolve the number that was supposed to be here (especially if it is a fire extinguisher and we know the fourth digit as well), or at least limit it to a handful of possibilities.

We now have the following solution for this puzzle from an archive document:

Room Type Serial Number
2-365 hose 752512
26-044 hose 750996
6-023 hose 752076
26-562 ext. 751088
16-034 hose 750484
4-001 hose 752089
E25-551 ext. 754797
E51-207 hose 753872
38-321E hose 751332
18-282 hose 750646

Plug the ten serial numbers into the formula given on the first page of this metapuzzle to get the final answer to this meta, 2545025.

Escher meta

In each set of three puzzles, one answer is the name of something seen (or possibly seen, anyway) in one of Escher's artworks. We found most of them in numbered figures in GEB. These are:
Puzzle Answer Figure
Tribar SYZYGY 48
These answers are applied to transpose the code strings found in this meta, in the given order (i.e. SHOEPRINT for the first code string, LEAFYLAKE for the second, etc.). The resulting strings should be written as columns and then rearranged so that the result makes sense. We did not find any specific ordering mechanism for this (it was not based on the figure numbers), but there is plenty of information available to solve it. In fact, we solved this with only 10 answers (missing the answers for 7, 9, and the tribar), and were able to determine all three missing answers, by locating the letters needed to complete words near the beginning of the text in the code strings and computing the offsets required to reach them. This leads to the following set of instructions, which are numbered here only for convenience:
  1. Begin at the Escher painting next to 24-608. At no time from now on should you walk up a flight of stairs.
  2. Walk toward the dark green lizard.
  3. Exit to your left.
  4. Find the floor with the A.P.C. Project P.E.P.R. sign.
  5. Go through the forest of carpets.
  6. Exit left.
  7. Find Board #AK220833.
  8. Find the wheelchair elevator close by.
  9. Go past the flying man.
  10. Exit,building by the exit closest to 755733.
  11. Go through the swinging double doors.
  12. Stand underneath the seventh sprinkler.
  13. Walk toward the pair of dragon eyes.
  14. Keep going.
  15. Go up a story when it's time.
  16. Go in the direction of the xylotone.
  17. Keep going.
  18. Turn away from the Marriott.
  19. Immediately after passing the teal arch, go through the door on your right.
  20. Go through the first door on your left.
  21. Pass bulletin boards on your right.
  22. Stand under the exit sign.
  23. Go straight until the third light fixture.
  24. Walk to the Boston Edison Company.
  25. Keep going; at the next choice, choose blue over green.
  26. Soon, you will be tempted to go up a story, but don't. Instead, keep following the white strip.
  27. Enter next building, then open door slowly.
  28. Take the next door on the left after passing by a blackboard.
  29. Keep going.
  30. Go down stairs at the next opportunity.
  31. Make a hairpin turn at Halsey Taylor.
  32. Exit building.
  33. Walk toward the Blue Fearsome Idol.
  34. Enter double door immediately behind the Blue Fearsome Idol.
  35. Go up two stories at the next chance you get.
  36. Walk toward the coke machine.
  37. Pass underneath chilled water supply pipes.
  38. Pass through double doors.
  39. Go by XYZ.
  40. Go through double doors.
  41. Stop at the mail drop.
  42. Walk to the drinking fountain.
  43. Go through green door.
  44. Enter the next corridor on your left.
  45. Go through the sixth door on the left.
  46. Take an immediate right, then an immediate left.
  47. Look for a wolf, a castle with gates, and a dove on your left.
  48. Take the next available left.
  49. Walk toward BOSTON.
  50. Walk toward Boston.
  51. Stop before the closed double doors.
  52. The inscription just on your right gives the teleport spot.
  53. Teleport to: 75 26 50 40 14 72 105 18 102 11 67 107 106 37 22 45 49.
  54. Enter where it says Do Not Enter.
  55. Go through the first available double doors on your left.
  56. Go up three stories
  57. Find signs with black on white arrows.
  58. Follow the direction pointed to by more arrows.
  59. At the next intersection, turn toward the direction of the light switch.
  60. Keep going.
  61. At the next intersection, pick the locks.
  62. Keep picking locks until you run out of locks.
  63. Don't enter the hallway with David waiting at the end.
  64. At the next fork, take the blue door.
  65. After passing the green door, go through the next door.
  66. Go to the nearest elevator.
  67. Walk toward the other elevator.
  68. Find the regular pentagon. Go to it.
  69. Go through the door located on the left of the pentagon.
  70. 26 16 46 9 29 36 18 2 18 38 12 47 32 14 39 13 10 29 11 5 4

Some comments:

We followed this runaround up to the Boston Edison Company, where we performed the letter extraction described in the Tribar, and then to step 32, which puts you into the alley between buildings 35 and 37.

But a newer archive document gives the final destination as the elevator in the lobby of E51, next to a sculpture by Frank Stella. We know from this article that two of his works were installed at MIT in 1995, Loohooloo and Heads or Tails. This page says Heads or Tails is installed in the E51 lobby (it also says it was acquired in 1997, in conflict wit the other article, but I'm ignoring that).

Whatever text we are extracting from in the last step gives the final answer to this runaround, FINGERYOYOATGAPPLECOM. We can reverse the code to get ?O?MO???GLCAPA?I?Y???????F??E?G???R?OP??????NT but except for the word CAPACITY it's not really enough to know what it says.

Bach meta

The answers are titles of musical works:
Puzzle Answer
1C Sweet Dreams (the puzzle confirms this is the song by Air Supply)
2C Rockin Robin
3B Enigma Variations
4A Adeste Fideles
5A And Can it be that I Should Gain
6B The Music of the Night
7C Mozart's Fortieth
8C Blue Suede Shoes
9B Honesty
10A Somewhere Over the Rainbow
11A Try to Remember
12B Theme from Deep Space Nine
Tribar Ode to Joy

This meta was unsolvable, even during the Hunt in which it was run. There were attempted corrections given (which are not in the archives), but even then it had to be scrapped. We have noticed, for instance (even after considering that notes connected by a tie are treated musically as a single note), that staff 13 contains 15 notes, while it should only contain 14. (An errata list since obtained indeed noted there was an extra note in that staff, the fourth from the right.)

Even if we did manage to find all the correct songs, and the correct music for them, and resolve all the other errors, in order to find the runaround path, the solution then depends on the letters on the window panes in the doors along the path it describes. While many of these door inscriptions have been around for ages, they do sometimes change, and building 6 in particular was heavily remodeled several years ago. Even one changed door inscription could lead to wrong letters in the answer we get from this meta -- which the puzzle tells us will not be intelligible text, so we would never know.

Ultimately the answer had to be given to teams. This answer, per the instructions, is a string of gibberish letters that presumably the answers to the other two metas tell us how to decode. Mark Gottlieb describes the event in his 1998 thesis, Secrets of the MIT Mystery Hunt: An Exploration of the Theory Underlying the Construction of a Multi-Puzzle Contest:

The error in the 1996 Hunt was major and it was handled extremely well by the Puzzlemasters. This Hunt had three separate endgame puzzles; only one was broken. The team in the lead (Chaos; again, this was my team) had made great headway into the flawed puzzle; no other team was able to begin solving it. Chaos held approximately a five-hour lead over the second-place team based solely on the progress made on this endgame. This puzzle hadn't been test solved, so Chaos was actually the first group of people to attempt it. The puzzle was riddled with errors and subjective musical interpretations, so Chaos had worked closely with the PM's on this puzzle for a number of hours. (This collaboration allowed the PM's to correct their puzzle for other solvers and it allowed Chaos to make progress on it.) After a while, it became clear to both parties that this puzzle could not be successfully solved; meanwhile, the rest of the teams were complaining that they couldn't even begin to try. This endgame, the culmination of one-third of the contest, would have to be scrapped . . . the PM's released the answer to Chaos, waited thirty minutes to respect Chaos's lead, then gave everyone else the answer. Chaos went on to win the Mystery Hunt by that thirty-minute lead.

Despite this, tacotortoise on Livejournal (not to be confused with the Tortoise in this hunt) attempted to solve it anyway. He figured out Music of the Night and Adeste Fideles as two of the missing answers by examining the available notes. In the following images, each tune is marked with these abbreviations under each note:

Any note with a question mark is uncertain. Comments about these appear after each page. Some general comments from tacotortoise: "They seem to be inconsistent about whether accidentals carry through the line. If there is an accidental on a note, I would trust it, but be wary of other notes. Some of the durations in DS9 may be inaccurate; it has some irregular rhythms that are hard to transcribe. BSS and SD both get a little shaky around the third page; I don't trust their transcriptions (or lead sheets) at all. For BSS, they seem to be basing the melody off of Elvis Presley's version, but transposed from the key of Bb to the key of D. Or, again, their sheet music may have been a bit off."

In line 1, DS9 should be a 16th note G. In line 3, SotR should be a quarter note A above the staff. In line 9, AF should be a quarter note B natural, and DS9 should be a 16th note G.


A newer archive document (page 6 here) gives the note sequence as G F# F E E G F# G A E Eb D B C D D D C B A Bb A G F G B C B A Ab D G E C F E D C. (It has note lengths and indications of which notes are in a higher octave, but those aren't needed.)

Additionally, the tribar solution gives us a starting point, the 3rd segment of the path which goes by 6-207. Given that, we can trace out almost the whole path:

I couldn't place the last 4 notes. The A flat (note 30) has to be the one on the 3rd floor; out of the other A flats (stairwell in building 5 between 2nd and 3rd floors, building 2 1st floor, and building 7 basement) the first two do not have the required connections to both an A and a D, and the last does, but the A has no connection to a B.

But even so, we would be extracting a set of letters from the doors which are going to be impossible to confirm today, which we're told will be gibberish.

This erratum email (page 1) (2) gives the complete sequence of doors to extract from, after the deletions for the meta, and the letters extracted from them. We don't know how many (if any) doors will match on each hallway, but it mostly follows the path I marked above, except for some discrepancies in building 2 (visiting the second floor and then the basement before the first floor).

The Conclusion

The solution to the Godel meta is a telephone number. At the time of the hunt, there was an answering machine message there which tells you to replace each number by the first letter of the corresponding word on page 302 of the book.

The solution to the Escher meta told us to finger yoyo@atg.apple.com. This led to a plan file containing the following numbers:

196 333 25 176 211 150 419 413 100 389 252 4 317 22 427 30 266 84 435 104 329 70 306 293 138 48 243 151 60 277 112 26 305 58 236 73 99 48 325 241 118 49 301 253 335 12 164 48 327 230 5 107 388 283 341 256 155 13 91 70 116 389 187 224 279 29 376 79 437 92 343 212 7 280

Using the method described on the answering machine, this decodes to copyafsmathlsaumichedugroupfactimhsujunkfootoathenaaddpgppgpfoo

Meaning to copy /afs/math.lsa.umich.edu/group/fac/timhsu/junk/foo to athena, then add pgp, then pgp foo.

The PGP passphrase to decode the file in the string of letters is obtained from the Bach meta. This requires actually following the meta path, which I couldn't finish, and which would probably not have all the same door numbers/letters as it did in 1996. But the newer archive solution file has this file, starting with "Hooray".

This file tells a story using the Tortoise and Achilles characters from GEB, providing a reason for them to have traveled to the Coney Island Ferris Wheel in the Little Harmonic Labyrinth story at page 103 of GEB, during which they get kidnapped. The story includes a poem about twirling an umbrella by moving some of its letters from one end to the other to make it a brellaum or laumbrel, and then it includes a uuencoded zip file.

I sent the image of uuencoded text through OCR with a lot of manual checking afterward, but I couldn't get a valid zip file out of it. Here's the uuencoded text I came up with.

You were supposed to figure out from the poem that the uuencoded text is broken and you need to fix it by replacing every U with M, M with B, and so on through UMBRELA, with A changing to U. That got me to this (mostly) corrected uuencode which gives a file fixed enough to unzip, but there are errors in two of the files which I was unable to find.

One file is a note from Achilles, which just comcludes the story and tells solvers the other files are the original ones that Hexachlorophene J. Goodfortune replaced with the ones to trap Achilles and the Tortoise during their own search for the coin. Each of these gives us yet another manipulation to apply to the metas.

File G

To solve this puzzle, you must solve the ordering puzzle implicit in the Tortoise and Achilles dialogue in the Subjunc-TV Repair Manual (the puzzle packet) in the flavor text of the Godel puzzles.

1A This is where they started after drinking the pushing potion to get into the manual. They are starting to follow notes they made before taking it. They saw this part of the manual before pushing in.

2B They didn't see this part of the manual before pushing into it, but Achilles didn't realize until now there were such parts.

3C They haven't seen a single living thing since entering the manual. They just came from the cwm finks message.

4C They've done the minesweeper and now it's getting dark "again", and Tortoise is ready to go back (out of the manual). They have been through 27 sections of the manual.

5B It's Sunday. They haven't slept for 24 hours. This is "just about" the last section of the manual and Achilles says they can take a nap.

6A Achilles is ready for "another" snack.

7A They just woke up so late Saturday morning it's almost Saturday afternoon, after being up pretty late Friday night. This is the cwm finks puzzle.

8B They didn't see this part of the manual before. Achilles makes up a meaning for RICERCAR as an acronym involving chess, which is the puzzle here. And Achilles suggests taking a break to eat; the Tortoise brought plenty of food.

9C Achilles and the Tortoise are confused to encounter the versions of themselves who live in the repair manual. They just came from the cryptogram (clued in part by the Tortoise arriving ahead of our Achilles).

10C This is the cryptogram. With this stop they have visited every part of the manual they examined before drinking the potion. The Tortoise leaves this one before Achilles.

11B This is the minesweeper. The manual's versions of Achilles and the Tortoise are in the puzzle, and Achilles recognizes them and decides to stay away, unlike the other time they encountered them.

12A It's 6 AM Sunday. They drank the pushing potion on Friday.

There is flavor text in the non-Godel sections as well, but most of it doesn't give clues that helps place them, just hints for the puzzle they are on. But consider these:

So we can start by putting 1A first, and based on the things that come immediately after specific puzzles, put 7A immediately before 3C, 11B immediately before 4C, and 10C immediately before 9C. We also know 3C comes before they encounter their other selves in 9C, and 11B is after that. So we can order these sections: 1A ... 7A-3C ... 10C-9C ... 11B-4C.

There are several clues that give us some sort of time:

In 4C they say it's the 27th section, so they have 9 left. So this had to be before 5B ("just about the last"), so 4C is on Saturday evening. So 4C comes between 7A and 12A, and we have 1A ... 7A-3C ... 10C-9C ... 11B-4C ... 12A ... 5B.

In 11C they talk about it being too bad the Anteater couldn't stick around, and he was only there for an hour, so this must have been right after that. The Anteater was in 7C, a segment in which they had notes from before pushing in. So 7C had to be before 10C, where they say they've now visited all the sections of the manual they read before pushing in, and 11C, which they visited just afterward, is also before 10C. We've already established 10C is before 4C, which is on Saturday. Since they started Friday, 11C must be on Saturday, and 6A was on Friday, and before 7A, which was on Saturday.

They eat for the first time in the manual in 8B, and again in 6A, so 8B was before 6A

Section 2B is the first time Achilles sees a manual section that they didn't see before pushing in, and Tortoise says in that scene there were several of those. 8B is "another" such section, so it comes after 2B.

So now we can place the Godel sections in order:
1A 2B 8B 6A 7A 3C 10C 9C 11B 4C 12A 5B
And follow the instructions we were given:

If we were meant to use H, then the AP in the shifted sequence would have been SI. It doesn't affect either extraction.

For the last bit, we're supposed to pick 7 random points on a circle, draw all possible chords between pairs of the points (assuming no three chords intersect in the same point inside the circle), count the number of regions the interior of the circle is divided into (57; see below), and subtract 10 to get 47. So the answer to this part of the final meta is RO47

A convenient way to count the regions is to note that there are two at the edge between each pair of points, and three for each point facing inward. Now considering just the heptagon inside all those regions, there is one region at each vertex and one in the middle of each edge. Inside that is a 7-pointed star made of one region at each point, and a single heptagon in the center. So there are eight sets of seven, plus one, making 57.

File E

Each Escher section of the manual has an answer that is an object that appears in one of Escher's works in the book. We have to find the page numbers, interpret each page number as a number in base 36, add these up, multiply by K (we are still working in base 36, so this is 20), and then add 400 Memorial Drive.

Funny thing, at the time I wrote the table for the Escher meta, I didn't have this text, but now I can complete the table and add page numbers. Clothespins appear at the lower right of Waterfall, where a woman is hanging clothes on a line.

The bivalve (a shellfish like a clam, oyster, or mussel with a two-part shell) was difficult to find. Mosaic II on page 61 has a bunch of animal shapes but not a bivalve. Castrovalva on page 550 has a snail in the detail at bottom left, but that's not a bivalve. There are also pictures with crabs and ants, not bivalves. There are two Escher pieces that undeniably contain bivalves, Shells and Starfish from 1941 and Sea Shells from 1949, which has scallop shells, but they aren't in the book. I ultimately decided it had to be the shape on the floor (ceiling?) in rthe middle of Convex and Concave on page 107, which I had taken to be an architectural element and not an actual shell.

It only counts manual sections, so we exclude the answer from the tribar.

Puzzle Answer Figure Page
3A POTSHERD 71 399
6C BIVALVE 23 107
7B BANNER 13 57
11C ECHECS 8 14
12C DINING 22 98
Tribar SYZYGY 48 250 (excluded)

So we do the base 36 math, getting 12-17-34 or 16198 in decimal. Multiply by 20 to get 323960. This is 6XYW in base 36. Now are we adding 400 Memorial Drive with the 400 is base 36? That is what the document appears to say. That would make 71YW.

If we are including SYZYGY on page 250, we get 84QW, 88QW after adding 400 in base 36. None of these make any sense. There is nothing with an address of 71, 84, or 88 on Memorial Drive.

So the bivalve is probably elsewhere.

File B

The errata emails come to our aid now. we have to add up all the room numbers of the doors used to produce the PGP code, including the building numbers but excluding any letters in the room numbers. Those are 8-102 8-114 6-207 6-215 6-216 6-218 6-218 6-218 2-221 2-034 2-038 2-040 2-048 2-051 2-052 2-108 4-131 4-133 4-134 4-138 4-140 4-141 4-142 4-144 4-204 4-205 4-208 4-212 10-322 10-390 10-100 3-103 3-107 3-108 3-140 3-164 3-166 1-304 1-307 1-163 1-165 1-170 1-181. I assume it's meant to concatenate the digits and treat these are 4 or 5 digit numbers. This gives us 176922 as the value of x.

The next part says to take the three-letter word in large letters in Lobby 7 high above the entrance to the infinite corridor. The inscription is Established for Advancement and Development of Science its Application to Industry the Arts Agriculture and Commerce. Charter MDCCCLXI. And this photo shows us the the 3-letter word we want is FOR (only the side of Lobby 7 going into the Infinite Corridor has the blue-green doorways seen at the lower right).

We're supposed to shift the first letter forward by the sum of the first and fifth digits of x. Those are 1 and 2 so we shift 3 to I. Shift the second letter backwards by the sum of the digits of the of the room number of the Department of Alchemy, including the building number. It's easy to find this is 2-214 so we shift by 9. Then further shift backward by the last digit of x, which is 2. We end up with D We don't change the third letter. So IDR is the first part of the answer to this puzzle. The second part is the remainder when x/2 is divided by 4423, which is 1.

The Coin

We ended up with RO47, 71YW Memorial Drive, IDR1. None of those answers make a lot of sense. The coin map tells us the final clue was FIRE DOOR 4-369, which doesn't look like anything we got.