Noah and I spent the weekend at the MIT Mystery Hunt, a weekend long puzzle competition held at MIT each Martin Luther King day weekend. Teams of 20-120 people work to solve an astonishing collection of puzzles, starting at noon Friday and going until sometime on Sunday. There are puzzles of every sort — wordplay, crosswords, logic, bizarre images, scavenger hunts and new puzzle forms invented for the day — many of whose answers feed into other puzzles. The puzzles and solutions are now available: this page explains the plot of the hunt, while this page shows you all of the puzzles as we saw them.

I thought I’d single out some of the puzzles that might be particularly enjoyable to the mathematically minded. In each case, the puzzle should output a word or short phrase. My descriptions below contain slight spoilers, in order to be friendlier to people who are not familiar with the Hunt, but I never spoil the interesting part of the puzzle.

Interstellar Basic Algebra What are the images, and what could the letters represent so that the equation holds? And once you know that, what goes on the right hand side of the other equation? (Math level: linear algebra)

Dual Singularities For each clue phrase, one answer goes in one crossword grid and one in the other — except for when an answer jumps across grids! Our team’s crossworders figured out all the clues but couldn’t figure out how the jumping worked, at which point I found elementary topology extremely useful. (Math level: basic topology)

Malthusian Catastrophes A collection of lengthy, but amusing, geometry and calculus problems. If your students ever get tired of textbook related rate problems, you could use a few of these. When you get the dates at the end, figure out how to convert them to letters to read a final clue phrase. (Math level: geometry and precalculus)

Plan 4 From Outer Space In the first six sets, each letter represents a different digit (and 4 represents itself.) The encoding varies from set to set. Use the top two equations to figure out which letter is which, then figure out what you are supposed to do with the Greek letters and the final set. I had a lot of fun with this. (Math level: trigonometry and calculus, plus logic)

The Sexaholics of Truthteller Planet An amazing logic puzzle, where lying is an STD. It seemed like there were hours when all I heard from one corner of the room was variants of “So, if Oliver is a knave, then Killbott slept with Greasemaster on the third night.” When you finally solve all the logic, figure out how to convert the infected sexaholics history into letters to read your answer. (Math level: basic logic, and lots of it)

Cross Something-or-others I’m not really a fan of Cross Sums, but the members of our team who like them loved this one. Once you solve everything, there is a final step which outputs an English word. (Math level: arithmetic and logic)

The orbital nexus meta-puzzle In this round, every puzzle had four versions, which were rotated periodically (unannounced to us) on the webpage. There was also a java applet showing moons traveling around a planet. I can’t think how to link to this as a puzzle you can solve, but you can read the solution here and think about how to do the computations. (Math level: basic number theory)

Genetic Struggle This puzzle is about reconstructing evolutionary history from genetic data. Sadly, although I’ve thought about the actual biological problem a fair amount, I was far less effective than my team mate who knew no biology but had a better intuition for puzzle structure. Nonetheless, thinking about how to solve this puzzle should be a good introduction to thinking about algorithms which might work on real world data, a fascinating research topic. (Math level: graph theory, statistics)

Also, some puzzles which contained no math, but I thought were awesome: Mary Ka-Ching’s, Space Invader, The Comedy Planet, Featuring Sid!, Sorry, Wrong Number, The Combatant’s Guide to Zyzzlvaria, The Fifth Element (and 35 More), The Satellite of Love, Reflections on a Milky White Steed Who’s Quite Amphibious Indeed, Where the Hell is Captain Blastoid?, and I’m Feeling a Little TwitterPetted.

TwitterPetted is an example of the sort of puzzle that I think most people would really enjoy, but is obscured by the traditional lack of directions, so let me explain a little: These are 96 twitter messages, sent by 24 fictional pets to their 24 owners. For example, message 9 — “Awk! I’m just as scurrilous as my Shakespearean counterpart” — is sent from Iago, the parrot in Aladdin, to his owner Jafar, whose e-mail is *the_viz*. Got it? Good, now what are the other 95?

Finally, thanks to my teammates on Metaphysical Plant for being such excellent company throughout the weekend, and to the Bombers for writing such an amazing hunt!

“Calling You from My Cell” also had some math in it (together with recognition of phone tones and bird calls). “Bad Eggs” also had some elementary math of the most inglorious sort. Both are from Astro Jail.

Ugh I was out of town. Otherwise I love this stuff. What team were you guys?

David and Noah were on Metaphysical Plant (I think this is the Random team). I was on Project Electric Mayhem. Last year, the math department had a team called , but I guess it didn’t coalesce this time. Someone asked me to help organize this year, and I said no, so I feel a little guilty.

We were indeed on Metaphysical Plant. It’s actually a little more complicated than saying that we are the Random Hall team. I was on the Random Hall team from 2000-2005, whose name was Physical Plant most of those years. In 2005, we won. Half the team (including Noah and I) went on to write the SPIES hunt in 2006, the other half remained the Random Team. After SPIES, we decided not to join back together. Metaphysical Plant is more or less the people who wrote SPIES. We have a large number of Random alumni, but no current Random students. There is still a team based out of Random; it has gone through many names, most recently “Off by .”