# What is the most difficult logical puzzle

## The most difficult puzzle in the world

Every January, over a thousand puzzle freaks gather at the Massachusetts Institute of Technology for the MIT Mystery Hunt.

If you enjoy puzzling and are done with the daily crossword puzzle and Sudoku in the newspaper before you have finished your breakfast coffee, then you should perhaps think about the following brain twister: «1. Obtain the following resources: five armless chairs, one chair with armrests, six team members, three metal cans of red, yellow, and blue paint, three watering cans of different sizes, and a live duck. Never put the duck's life at risk. No animal should be harmed while looking for the coin. "

This is the first of 29 instructions in the «Duck Konundrum», a puzzle game like you have never experienced before. Unless you've already taken part in the MIT Mystery Hunt, the January scavenger hunt held at the Massachusetts Institute of Technology, where the most gifted puzzlers and puzzle solvers in the United States and elsewhere seek out a hidden coin. The quirky venture lasts 48 to 72 hours and is fed by large amounts of junk food, adrenaline, and insomnia.

The tradition dates back to January 1980 when Brad Schaefer, then a PhD student at MIT (and now an astronomy professor at Louisiana State University), conducted the first treasure hunt. Schaefer also organized the three following scavenger hunts, since then the search has been carried out without a ladder, rather it is always the winners of last year's competition who have to devise and organize the next round of puzzles. This rule ensures that the same team does not dominate the competition year after year, and it also makes puzzle development a collective task, as it takes more than one head to seriously test groups of a hundred or more die-hard puzzle addicts .

Brad Schaefer came up with the first treasure hunt on his own. He handed out a sheet of paper with a dozen tasks to the 300 or so people who had gathered in the entrance hall of the MIT main building on Friday afternoon. The answers to Schaefer's tasks, when combined correctly, gave clues to the whereabouts of a coin (a very rare penny with an Indian head) that was hidden somewhere on campus.

In one task of Schaefer's first guessing game, you had to find out which “globular cluster is closest to Cor Caroli”; another simply referred to a blanket poster in building 7 on campus. A small piece of text, written in a strange font, looked even stranger. The participants had to find out for themselves that it was written in the early ancient Mycenaean script Linear B. To make sure things weren't too easy, Schaefer had removed all of the texts about Linear ?? B from the MIT libraries. "I was sure it was going to be an incredibly difficult task, but it turned out to be one of the easier ones," he recalls. He had expected the treasure hunt to last the whole weekend and promised to give further tips on Monday morning if necessary, but the ordeal lasted less than 24 hours.

Mystery Hunt 2000, Puzzle 5.4

Resolution here

As Schaefer quickly found out, the hardest thing about the Mystery Hunt was setting up sufficiently difficult tasks. "The tasks I invented in the 1980s would be trivial by today's standards." Chris Morse, a former MIT student whose team has won three times, agrees: "With the help of the Internet, you could have solved the first puzzle game within an hour today." The harder nuts that are served today keep around a thousand people captive for two or three days. Often tasks are given that have never existed in this form before. On the “Nature Walk” in 2002, for example, the participants were given a list of numbers and a few photos of statues and had to find out for themselves what to do with them. The numbers corresponded to tablets attached to trees on campus, and the final answer to the puzzle, "Andrew Carnegie," came from the tablet on the last tree.

The first thing you have to do in a mystery hunt is to find out what the tasks are. Often the puzzles contain no or only hidden clues as to what needs to be found out. In the 2005 riddle, which was devised by Dan Katz, an MIT graduate and inventor of the duck game mentioned above, the participants received nothing but a list of film titles and dates. As it turned out, all of the films on the list starred in actors who portrayed a villain in the 1960s television series Batman. Cesar Romero, for example, played the joker. But the year given for the film "Crooks, Crowns and Jewels", in which Romero also played, was eight years off. This information in turn had to be interpreted as referring to the eighth letter of «The Joker»: R. All letters obtained in this way, if arranged correctly, resulted in the final note: «She wrote Emma» - what was meant was « Jane Austen ».

Mystery Hunt 2001, Puzzle 4.9

Resolution here

Other puzzles seem less complicated at first glance, but they take a surprising turn. One thing, for example, could not be solved unless a map was viewed under UV light. For another task, you had to know that the basketball game, which was processed in the book "Forty-eight Minutes" literary, had actually lasted 53 minutes instead of 48. The 2007 Mystery Hunt also had its pitfalls: It revolved around a crossword puzzle that, instead of being projected onto a flat newspaper, had to be viewed as a borderless, two-dimensional object.

Katz's duck riddle, the "Duck Konundrum", works in reverse. Instead of being stingy with instructions, here you get instructions that are as incomprehensible as possible. The people and the "duck" have to be moved from one chair to another, the underside of the chairs has to be labeled with different colored letters and the chairs have to be rearranged and turned around until the underside of the chair can be seen to be deciphered. As far as is known, no live ducks have been used to this day. One can therefore assume that no animals have been harmed in this treasure hunt, as one of the rules requires; therefore human representatives had to take on the role of the live duck and temporarily sit on the lap of other players or adopt other unnatural postures.

In contrast to the past, when the Mystery Hunt consisted of a colorful palette of mixed tasks, today's events have a theme and a plot. At the start of the treasure hunt in 2003, the members were hired by a company reminiscent of Enron, which seemed a rather boring start. But the next task showed several pairs of letters, ER KE TH LL ED TA PI, which, rearranged, resulted in “Take the red pill” - a famous saying from the film “The Matrix”. Then the participants met the film character Morpheus and found out that they themselves were moving in a kind of matrix.

This year's hunt also had a hidden theme. It started innocently when the participants had to attend a course on "How to be really good". But before they knew it, they had sold their souls to the devil. To get them back, they had to travel through hell - a place where puzzles cannot be solved - and take a crash course in How to Get Really Bad.

For some years now, all tasks have been set in stages instead of all at once. So the participants get something new on offer from round to round. The solutions to individual tasks are used to solve “meta-tasks”, the solutions of which are in turn required to answer metametas-puzzles. Not only has the treasure hunt become much more sophisticated over the years, but the number of participants has increased as the complexity of the plot grows. Nowadays, up to a thousand people come to MIT for the puzzle weekend, and another thousand are at home at the PC to help out.

The Mystery Hunt has found many imitators, for example The Game at Stanford University or the Microsoft Puzzle Hunt, but the treasure hunt at MIT has, to use Morse's words, “remained the measure of all puzzle games”. Katz agrees: “When it comes to quirkiness and madness, the others can't hold a candle to us. I haven't heard of any riddle that keeps so many people busy for so long. "

At the beginning of the hunt, each of the thirty or so teams set up a base camp in a student dormitory or seminar room made available by MIT for the weekend. The team members equip the headquarters with sleeping bags, reference books and computers and stock up on coffee and food such as Cheetos, Doritos and M? &? Ms. With this equipment you will feel up to any challenge.

The largest teams have a hundred or more colleagues. This requires a considerable amount of coordination and a strategic division of labor. These groups usually have a central database on which each team member can follow the collective progress in solving each task and, if possible, make a contribution. Katz prefers to work in groups of two dozen people: "If you yell and can no longer be heard by everyone in the room, I've exceeded the upper limit for me." Some puzzle fanatics see the Mystery Hunt as a recommendation for MIT. “There are students who only enroll here because of the treasure hunt,” claims Schaefer, “and who keep coming back as alumni after completing their studies. Some of them have now achieved fame and honor in national puzzle competitions. "

Looking back on what he started almost three decades ago, Schaefer is sometimes amazed at the enormous amount of manpower and time that was invested in developing and resolving these insane puzzles. “You could work out how many hours mankind has lost over the years,” he muses. "But maybe the years of brain gymnastics have unexpectedly borne fruit elsewhere."

And Morse, who has been part of every treasure hunt since the mid-1990s, wonders “what would happen if all these people, who come here from all over the world every year, do such amazing intellectual feats - if all these people do one instead Would seek cures for cancer ». But after a while he comes to the conclusion that these people probably need such an outlet and that events like the Mystery Hunt might help them move forward with important things in everyday life like the fight against cancer and the like.

So maybe the scavenger hunts aren't a complete waste. Perhaps the attempt to wrest a meaning from such a nonsensical thing as the duck riddle will turn out to be a profit in the end: «4. Get the duck to sit under chair # 5. If she's stubborn, entice her with food. Be kind to her and she'll end up playing along. Ducks love scavenger hunts. " Apparently people too.

Steve Nadis is a science journalist. He lives in Cambridge, Massachusetts (USA).

Translation: Robin Cackett, Berlin.

Archive of past Mystery Hunts at www.mit.edu/~puzzle.

This article comes from the NZZ Folio magazine from December 2007 on the subject of "puzzles". You can order this issue or subscribe to the NZZ Folio.