Tetris

Tetris is a computer and video puzzle game created in 1985 by the Russian computing engineer Alexey Pajit-nov. It is the most widely reproduced game of all time, appearing on 55 game platforms, including every major console and computer system; on mobile phones; and in interactive art exhibitions. It continues to be popular among a wide variety of casual and serious gamers, appearing second in IGN Entertainment's Top 100 games of all time in 2007.

The success of Tetris derives from its simple but addictive game play. A sequence of regular geometric tiles, each composed of four squares arranged into seven basic shapes, falls relentlessly from the top of the play area to form a stack at the bottom. As they fall, the player must rotate and guide the tiles, attempting to slot them into the stack below so that no gaps are left between them. When a single line of the stack is filled, it is removed from play and the tiles above drop down to replace it. Points are awarded for the number of lines removed during the course of the game. The more points the player accumulates, the faster subsequent tiles fall. There is no way to win Tetris: the game ends when the stack of tiles inevitably overwhelms the play area and no more tiles can be introduced into play. The reward of the game is therefore derived from achieving high scores, and its addictiveness arises from the tension between the relentlessly falling tiles and the growing stack at the bottom of the screen.

Subsequent versions of Tetris have generally retained the basic design, while adapting some of the game mechanics and adding new features. In the original version, the removal of lines from the stack could lead to tiles floating over empty space, but a variation allows tiles to fall into these spaces, setting off chain reactions that cascade through the entire stack. Other common variations relate to the number of tiles shown in the preview panel prior to entering into play, the ability to reserve tiles in the preview panel for later use, and the ability to prerotate tiles before they enter play. Recent releases have also tended to vary the game play, introducing speed rounds to compliment the original endurance challenge. However, one aspect of the game subject to little variation is the field of play—normally 10 squares in width by 20 squares in height.

Tetris is notable as the only game developed in Russia to achieve worldwide success. It was also the subject of a protracted intellectual property rights battle. Because of confusion in the sublicensing of the game, by the late 1908s, half a dozen game publishers claimed ownership of some rights to reproduce Tetris. The dispute was resolved when Atari Games, whose console subsidiary Tengen had released a version of Tetris for the Nintendo Entertainment System (NES), sued Nintendo for infringement of copyright. Atari claimed to have acquired console rights from Mirrorsoft, a division of the U.K. media company Mirror Group, which in turn had acquired the rights from British software house Andromeda.

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