About Tetris
Tetris is a falling-blocks puzzle video game. Its name was derived its from the Greek numerical prefix «tetra-», as all of the pieces contain four segments, and tennis, favorite sport of the author.
A sequence of tetrominoes - shapes composed of four square blocks each - fall down the playing field. The object of the game is to manipulate these tetrominoes, by moving each one sideways and rotating it by 90 degree units, with the aim of creating a horizontal line of blocks without gaps. When such a line is created, it disappears, and the blocks above (if any) fall. As the game progresses, the tetrominoes fall faster, and the game ends when the player «tops out», that is, when the stack of tetrominoes reaches the top of the playing field and no new tetrominoes are able to enter.
There are the seven one-sided tetrominoes in Tetris as I, J, L, O, S, T, and Z - due to their resembling letters of the alphabet. All are capable of single and double clears. I, J, and L are able to clear triples. Only the I tetromino has the capacity to clear four lines simultaneously, and this is referred to as a «tetris».
Scoring
The scoring formula for the majority of Tetris products is built on the idea that more difficult line clears should be awarded more points.
Tetris game allows the player to press a button to increase the speed of the current piece's descent, rather than waiting for it to fall. If the player can stop the increased speed before the piece reaches the floor by letting go of the button, this is a "soft drop"; otherwise, it is a "hard drop". Many games award a number of points based on the height the piece fell before locking. If a piece is manually dropped x lines and locked, these versions will typically award points proportional to the number of lines that the player accelerated the piece. If a piece is not accelerated at all the player will gain no points for that piece unless a line is made.
Variations
Tetris has been subject to many changes throughout releases since the 1980s. It is difficult to place a standard on the game, as newer releases frequently progress it either to make the game better or to keep players interested.
Is it possible to play forever?
Players may lose a game of Tetris for the following reasons:
- They can no longer keep up with the increasing speed, or
- A specific implementation of the game without very responsive control and without lock delay fails to keep up with itself when the pieces' downward velocity is much more than the maximum lateral velocity the player can apply to a tetromino.
The reason has to do with the S and Z tetrominoes. If a player receives a large sequence of S tetrominoes, the naive gravity used by the standard game eventually forces the player to leave a hole in a corner.
Suppose that player then receives a large sequence of Z tetrominoes. Eventually, that player will be forced to leave a hole in the opposite corner without clearing the previous hole. Back and forth, the holes will necessarily stack to the top. Since the pieces are distributed randomly, this sequence will eventually occur. If played long enough, and the random number generator is theoretically perfect, any player will lose the game. Practically, this may not occur.
Effect of Tetris on the brain
According to Richard Haier, et al. prolonged Tetris activity can also lead to more efficient brain activity during play. When first playing Tetris, brain function and activity increases, along with greater cerebral energy consumption, measured by glucose metabolic rate. As Tetris players become more proficient, their brains show a reduced consumption of glucose, indicating more efficient brain activity for this task. The game can also cause a repetitive stress symptom in that the brain will involuntarily picture tetris combinations even when the player is not playing the game (the Tetris effect), although this can occur with any computer game showcasing repeated images or scenarios.