| In 1985, Alexey Pazhitnov invented Tetris as part | | | | instance, in the "Tetris Worlds" rules used in many |
| of a science project for the University of | | | | recent implementations, certain rare situations |
| Sciences in Moscow. The name Tetris is derived | | | | allow T, S and Z to 'snap' into tight spots, clearing |
| from the Greek word "Tetra" which stands for | | | | triples.) |
| four - as all the pieces in the game are made of | | | | It is believed to be one of the best selling games |
| four blocks. | | | | of all time, mostly due to it's availability on a great |
| Seven randomly rendered tetrominoes or tetrads | | | | amount of platforms. Tetris has been featured in |
| - shapes composed of four blocks each - fall | | | | Arcades, mobile gaming devices such as |
| down the playing field. The object of the game is | | | | Nintendo's Game Boy, mobile phones, PDAs, |
| to manipulate these tetrominoes with the aim of | | | | personal computers and of course the web. |
| creating a horizontal line of blocks without gaps. | | | | The music for the original Game Boy edition of |
| When such a line is created, it disappears, and the | | | | Tetris titled "Music A" has become very widely |
| blocks above (if any) fall. As the game | | | | known. It is a in fact a Russian folk tune called |
| progresses, the tetrominoes fall faster, and the | | | | "Korobeyniki". To this day it is estimated that two |
| game ends when the stack of Tetrominoes | | | | our of three adults living in the US identify the |
| reaches the top of the playing field. | | | | tune as "The Tetris tune". |
| The seven rendered tetrominoes in Tetris are | | | | Tetris is a registered trademark of the Tetris |
| referred to as I, T, O, L, J, S, and Z. All are | | | | Company LLC, but the game itself is not |
| capable of single and double clears. I, L, and J are | | | | copyrighted in the US (games cannot be |
| able to clear triples. Only the I tetromino has the | | | | copyrighted, only patented, and any Patent claims |
| capacity to clear four lines simultaneously, and this | | | | to Tetris would be expired by today) - which is |
| clear is referred to as a "tetris." (This may vary | | | | why many Tetris clones legally exist. |
| depending on the rotation and compensation rules | | | | Play a Flash version of Tetris at PlayedOnline. |
| of each specific Tetris implementation; For | | | | |