Originally a paper-and-pencil game by Richard Bartle. Now implemented as a game for use with the X Window System.

The basic idea is that there are two, or more, players who cast spells at each other to become the last man standing. Spells are made through a series of hand gestures. These gestures are performed simultaneously by all players. A player may cast a spell to distort another player's sequence of gestures (causing the opponent to make no gestures, a gesture specified by the attacker, or the same gesture as before).

The more powerful a spell is, the more gestures are needed. The chance of failure is large, because a spell can be interrupted by an opponent. For example Finger of Death (the most powerful spell, causing instant death) is: palm forward-wave-palm forward-fingers spread-snap-snap-snap-point (requires 8 uninterrupted turns). Amnesia (make opponent repeat last gestures) is as simple as: point-palm forward-palm forward (requires 3 turns).