Tetris

Tetris is a puzzle game designed and programmed by Alexey Pajitnov in the Soviet Union (present day Russia). It was released on June 8, 1984 in the USSR while he was working for Dorodnicyn Computing Centre in Moscow. The name, Tetris, comes from the word tetrominoes and Pajitnov's favorite sport, tennis. 
The Tetris game is a popular use of tetrominoes, the four element special case of polyominoes. Polyominoes have been used in popular puzzles since at least 1907, and the name was given by the mathematician Solomon W. Golomb in 1953. However, even the enumeration of pentominoes is dated to antiquity.
== Gameplay ==
A random sequence of tetrominoes—shapes composed of four square blocks each—fall down the playing field (a rectangular vertical shaft, called the "well" or "matrix"). The objective 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 ten blocks without gaps. When such a line is created, it disappears, and any block above the deleted line will fall. When a certain number of lines are cleared, the game enters a new level. As the game progresses, each level causes the tetrominoes to fall faster, and the game ends when the stack of tetrominoes reaches the top of the playing field and no new tetrominoes are able to enter. Some games also end after a finite number of levels or lines.
All of the tetrominoes 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". (This may vary depending on the rotation and compensation rules of each specific Tetris implementation. For instance, in the Super Rotation System used in most recent implementations, certain situations allow T, S, and Z to 'snap' into tight spots and clear triples.)
== History ==
Tetris has been involved in many legal battles. In June 1984, Alexey Pajitnov created Tetris on an Elektronika 60 while working for the Soviet Academy of Sciences at their Computer Center in Moscow with Dmitry Pavlovsky, and Vadim Gerasimov ported it to the IBM PC. Gerasimov reports that Pajitnov chose the name "Tetris" as "a combination of 'tetramino' and 'tennis'." From there, the PC game exploded into popularity, and began spreading all around Moscow. The most recent version of this port is available on Gerasimov's web site.
The IBM PC version eventually made its way to Budapest, Hungary, where it was ported to various platforms and was "discovered" by a British software house named Andromeda. They attempted to contact Pajitnov to secure the rights for the PC version, but before the deal was firmly settled, they had already sold the rights to Spectrum HoloByte. After failing to settle the deal with Pajitnov, Andromeda attempted to license it from the Hungarian programmers instead.
Meanwhile, before any legal rights were settled, the Spectrum HoloByte IBM PC version of Tetris was released in the United States in 1986. The game's popularity was tremendous, and many players were instantly hooked—it was a software blockbuster, with reviews such as in Computer Gaming World calling the game "deceptively simple and insidiously addictive".
The details of the licensing issues were uncertain by this point, but in 1987 Andromeda managed to obtain copyright licensing for the IBM PC version and any other home computer system.
For Amiga and Atari ST two different versions by Spectrum HoloByte and Mirrorsoft became available. The Mirrorsoft version did not feature any background graphics while the Holobyte version had a background picture related to Russian themes for each level. Games were sold as budget titles due to the game's simplicity. Spectrum's Apple II package actually contained three diskettes with three different versions of the game, for the Apple II+ and Apple IIe on separate DOS 3.3 and ProDOS 51⁄4" diskettes, and for the Apple IIgs on a 31⁄2" diskette, none of which was copy-protected: the included documentation specifically charged the purchaser on his or her honor to not give away or copy the extra diskettes.
By 1988, the Soviet government began to market the rights to Tetris, after a promotional trip to the country by Gerald Hicks, the one time United States champion of the game, through an organization called Elektronorgtechnica, or "Elorg" for short. Pajitnov had granted his rights to the Soviet Government, via the Computer Center he worked at for a decade. By this time Elorg had still seen no money from Andromeda, and yet Andromeda was licensing and sub-licensing rights that they themselves did not even have.
By 1989, half a dozen different companies have claimed the right to the game, but according to Elorg, were not legally entitled to produce an arcade version. They passed on the rights to Atari Games, while non-Japanese console and handheld rights were signed off to Nintendo. Tetris was on show at the January 1988 Consumer Electronics Show in Las Vegas, where it was picked up by Dutch games publisher Henk Rogers, then based in Japan, which eventually led to an agreement brokered with Nintendo that saw Tetris bundled with every Game Boy.
Tengen, the console software division of Atari Games, applied for the copyright for their Tetris game for the NES and proceeded to market and distribute it under the name TETЯIS: The Soviet Mind Game (with faux Cyrillic typography incorporating the Cyrillic letter Ya), disregarding Nintendo's license from Elorg. Nintendo contacted Atari and claimed that Atari had stolen Nintendo's rights to the game. Atari Games, who believed they had the rights, sued. With only four weeks on shelves, the courts ruled that Nintendo were the only company which had the rights to Tetris on home game systems, and Tengen's TETЯIS game was recalled, with an unknown number of copies sold. The lawsuits between Tengen and Nintendo over the Famicom/NES version carried on until 1993. 
Nintendo released their version of Tetris for both the NES and the Game Boy (the Famicom and Game Boy versions were developed by Bullet-Proof Software, Inc., who held the Japanese license, despite Nintendo's license to the game) and sold more than three million copies; some players considered Nintendo's NES version inferior because it lacked the side-by-side simultaneous play of Tengen's version, but Nintendo's Game Boy Tetris became arguably the most well-known version of Tetris, selling over 33 million copies.
In 1996 the rights to the game reverted from the Russian state to Pajitnov himself, who previously had made very little money from the game. In 1996, The Tetris Company was founded, claiming to hold copyright registrations for Tetris products in the United States and taking out trademark registrations for Tetris in almost every country in the world. They have licensed the brand to a number of companies, and the U.S. Court of International Trade and the U.S. Customs have at times issued seizure orders to preclude Tetris-like games from being imported into the U.S., though bulletins circulated by the U.S. Copyright Office state that copyright does not apply to the rules of a game.
In late 1997 and in mid-2006, TTC's legal counsel sent cease and desist letters to web sites that misused the Tetris trademark to refer to homemade tetromino games. Around 2009, TTC and Tetris Holding LLC brought legal action against BioSocia, Inc., on the grounds that BioSocia's "Blockles" game infringed on proprietary rights that were held by TTC and Tetris Holding LLC. On September 10, 2009, the legal case against BioSocia was resolved, with BioSocia agreeing to discontinue making the "Blockles" game available to the public. In May 2010 TTC's legal counsel sent cease and desist letters to Google insisting that 35 Tetris-clones be removed from the Android Market.
Category:Games that are rated E
Category:Games released on the Game Boy
Category:Games released on the Nintendo Entertainment System
Category:Games released in 1984