Tetrimino
Tetriminos (also referred to as Tetrominos, Tetrads or simply Blocks) are the main object in the Tetris series of games. Tetriminos are shapes all made up of four square blocks, and the main goal of all the games is to arrange them in a horizontal line in a well without a single missing spot (regardless of color or shape). Once this is done, the row of Tetriminos is cleared, the player is rewarded with points and the above lines of blocks all move down one row.
Bonus points are awarded for clearing more than one row at once. Clearing four lines is called a "Tetris", and is worth the most points. As soon as one Tetrimino is laid on the well, another begins to fall from the top of the well. If the blocks overflow and no more Tetriminos can be brought onto the well, the player fails and the game ends.
There are seven different types of Tetriminos all colored differently. They may be rotated as a group, even when first landing on other blocks or the floor, but their form will not change. In games, markers are usually at the floor to show where the Tetriminos will land so it is easier for the player. It is possible in some games to "hold" a Tetrimino (store it for later use, and use the one that came after).
