Nontransitive dice – how to win every time

[While I'm away for a week, I'm posting classic Boing Boing entries from the archives. Here's a gem from 2006.]

I'm reading a terrific book by William Poundstone called Fortune's Formula: The Untold Story of the Scientific Betting System that Beat the Casinos and Wall Street. On page 153 Poundstone writes about a 1968 dinner meeting between mathematician Edward Thorp and fund manager Warren Buffett. Poundstone mentions in passing that Buffett and Thorpe discussed their shared interest in nontransitive dice. "These are a mathematical curiosity, a type of 'trick' dice that confound most people's ideas about probability," writes Poundstone.

Curious, I googled "nontransitive dice" and found a nice description of them by Ivars Peterson at the Mathematical Association of America's website.

Peterson introduces the subject with this intriguing paragraph:

The game involves four specially numbered dice. You let your opponent pick any one of the four dice. You choose one of the remaining three dice. Each player tosses his or her die, and the higher number wins the throw. Amazingly, in a game involving 10 or more throws, you will nearly always have more wins.

The trick is to always let your opponent pick first, and then you pick the die to the left of his selection (if he picks the die with the four 4s, then circle round to the die with the three ones). It's just like playing Rock, Paper, Scissors -- only you get to see what the other guy picks in advance.

With these dice, you always have a 2/3 probability of winning -- what a great sucker's bet! Read the rest

Cthulhu Dice – Curse your opponents before you lose all your marbles and go insane

The Cthulhu Mythos is turned into a game of dice in Steve Jackson's Cthulhu Dice. The demonically beating heart of the game is a large, beautiful, and gem-like 12-sided die covered in Cthulhu-related runes. Each rune has a different effect in making one person or another go insane (or taking some of their insanity away from them). Players take turns choosing someone to curse and then casting the die against them. Every player has a stash of Sanity Tokens (little glass disks), a.k.a. “marbles,” and when you've lost all of your marbles, you go insane. But this is a game from the world of H.P. Lovecraft, so you're still not out of the game. Insane players continue to play just to try and drive other players mad. The goal of the game is to be the last sane Cthulhu Cultist standing. If everyone goes rubber room bonkers, Cthulhu wins.

Cthulhu Dice is very easy to learn and especially fun to play in situations where you want the social interaction of gaming, but don't want to play a long game, or you don't want to be tremendously engaged in the game you're playing. People always talk about “beer and pretzels” games, well this is a game you could actually play in a boisterous bar or as a sort of palate cleaner between main attraction games at a gaming night.

Cthulhu Dice Steve Jackson Games Ages 10 and up, 2-6 players \$7

Plastic dice in bulk

I carry 3 red dice in my back pocket so that I can play a game called Cee-lo with people that I meet. Like most betting games, Cee-lo has a rough reputation. But played among friends, not betting for money, it can be rather wholesome.

I really like being able to play a simple dice game with people for a few reasons:

- it’s a really fun game! - I’ve successfully played it with kindergartners and every age group above, - I’ve gotten mixed age groups to have a GREAT time playing, - It never runs out of batteries or needs to be upgraded, - it’s very portable, - it gets people to talk in real time, - I don’t have to hand an expensive device to other people or count on them having one, or having one compatible to mine. Read the rest