Alexey Pajitnov, a Soviet software developer, invented Tetris in 1984. Several firms have made it accessible for use on other platforms, most notably in the late 1980s when a legal battle raged over who should have ownership of the rights. Tetris was originally distributed by Nintendo for a long time until Pajitnov and Henk Rogers created the Tetris Company in 1996 to manage license. In Tetris, lines are formed by the player manipulating falling pieces of varying shapes (tetrominoes). After the finished lines disappear and the player is awarded points, they may continue by filling in the remaining spaces. It's game over when the unmarked lines rise over the playing area. The higher the score, the more time the player may purchase. Players in multiplayer games must outlive their opponents, and in certain variants, players may penalize opponents by completing a large number of lines. Some variants feature new rules, such as a mechanism for conserving pieces or a new display format that incorporates three dimensions.