Tetrominoes can be rotated ninety degrees on a block. The rotation can either be clockwise or counter-clockwise. Both directions can be useful in tight spaces. Rotation can be used to to get a tetromino to match the space around it and not create gaps. For example, I-Blocks might need to be rotated to cause a Tetris. Sometimes, a tetromino might need to be rotated into place at the last moment. An example of this is the T-Spin. A Tetromino cannot be rotated after a Hard Drop.