Crack Attack - OpenGL Linux version of Tetris Attack in which you can eliminate blocks horizontally or vertically. (Open Source, GPL) Black Hole - Tetris for Linux or Windows set in space with blocks coming from four different directions. Eittris - Tetris knockoff for Windows offering multi-person competitive play with up to four players and high scores on the web. U61 - Multiplayer network falling block based game for Windows or Linux. (Open Source, GPL) LTris - A Tetris clone for Linux. Tetris - Windows version with sound, and the ability to minimize to the system tray. Stacker Blocks 3D - A falling blocks game for Windows in the style of classic Tetris. However, unlike classic Tetris, Stacker Blocks uses Direct3D graphics to give the game added visual appeal. (Open Source, GPL) Quadra - Multiplayer internet Tetris for Linux or Windows. GLBlocks - Multicolor square blocks are falling; lines disappear when four segments of the same color touch. For Windows, and a port to Game Park's GP32 handheld gaming console.