Wikipedia:Tetris

Tetris (Russian: Тетрис) is a falling-blocks puzzle video game, released on a large spectrum of platforms. Alexey Pajitnov originally designed and programmed the game in June 1985, while working for the Dorodnicyn Computing Centre of the Academy of Science of the USSR in Moscow. Pajitnov has cited pentominoes as a source of inspiration for the game. He derived its name from the Greek numerical prefix "tetra-", as all of the pieces contain four segments, and tennis, Pajitnov's favorite sport.