tetris

The Tetris rules

1. There is a grid with a height of 16 blocks and a width of 10 blocks.
2. You have seven different tetrimino (a tetris piece) that are all composed of four blocks.
3. A new tetrimino appears at the top of the game's grid every time the previous one cannot descend and more (because the block below is already occupied or bacause you're reched the game's floor).
4. The game is over when a new tetrimino cannot appear anymore (because there is already a tetrimino at the top of the grid).
5. Every time a line if full (all blocks are occupied by a tetrimino part), it disappear and all lines above descend by one line.