Tetris has been embroiled in a large number of legal battles since its
inception. In June 1985, Alexey Pajitnov created Tetris on an Electronika
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 contraction
of "tetromino tennis". 
From there, the PC game exploded into popularity, and began spreading all around
Moscow. This version 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.
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.
By 1988, the Soviet government began to market the rights to Tetris through
an organization called Elektronorgtechnica, or "Elorg" for short. 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 claimed rights to create and distribute
the Tetris software for home computers, game consoles, and handheld systems.
Elorg, meanwhile, held that none of the companies were legally entitled to produce
an arcade version, and signed those rights over to Atari Games, while it
signed non- Japanese console and handheld rights over to Nintendo.
Tengen (the console software division of Atari Games ), regardless, applied
for copyright for their Tetris game for the Nintendo Entertainment System, loosely
based on the arcade version, and proceeded to market and distribute it under the
name TET??IS (with faux Cyrillic typography incorporating the Cyrillic
letter Ya), disregarding Nintendo`s license from Elorg.
Nintendo contacted Atari Games claiming they had stolen rights to Tetris,
whereupon Atari Games sued, believing they had the rights. After only a few (very
popular) months on the shelf, the courts ruled that Nintendo had the rights to
Tetris on home game systems, and Tengen`s TET??IS game was recalled, having
sold about 50,000 copies.