Tetris is an arcade game created in 1985 by Alexei Pajitnov in USSR. Geometrical forms scroll down one after each other and the player has to pile them up so as to form lines that disappear once they are complete.
In the game, there are 7 different pieces that can be in elongated, in square in S shape etc...
Depending on the versions of Tetris, the pieces have different colors. In the different levels of the game, the pieces scroll down more or less quickly, and the frequency of some pieces changes. This game, from the same times as Pac-man and Pong, requires reflexion and agility to pile the pieces up in the best way possible so as to make disappear the lines and score points.

The game Tetris was a huge hit at its time, and still has not evolved even though some derivate games from the first version were created in order to use the success of Tetris. Many Tetris games have been created for cell-phones or computer and it is still on of the most played game on computers. It has also been adapted for computer flash games and is therefore playable for free.