Welltris

First release: 1989
Developer: Sphere, Inc., Alexey Pajitnov, Bullet-Proof Software
Publisher: Spectrum HoloByte, Inc., Infogrames
Genres: Puzzle
Platforms: DOS, Commodore C64/128/MAX, Amiga, Amstrad CPC, Arcade

Welltris is a puzzle video game, developed by Doka and licensed to Bullet-Proof Software. Adaptations were made by Sphere, Inc for Spectrum Holobyte, and by Infogrames. It was originally released for DOS and Macintosh in 1989. It was subsequently ported to the Amiga and Atari ST in 1990 and the ZX Spectrum and Commodore 64 in 1991.