In 1979, Alexey Pajitnov joined the Computer Center of the Soviet Academy of Sciences as a speech recognition researcher. While he was tasked with testing the capabilities of new hardware, his ambition was to use computers to make people happy.[17]: 85 Pajitnov developed several puzzle games on the institute's computer, an Electronika 60, a scarce resource at the time due in part to CoCom.[18]: 298 [13]1:50 For Pajitnov, "games allow people to get to know each other better and act as revealers of things you might not normally notice, such as their way of thinking.
In 1984, while trying to recreate a favorite puzzle game from his childhood featuring pentominoes,[19] Pajitnov imagined a game consisting of a descent of random pieces that the player would turn to fill rows.[17]: 85 Pajitnov felt that the game would be needlessly complicated with twelve different shape variations, so he scaled the concept down to tetrominoes, of which there are seven variants.[20] Pajitnov titled the game Tetris, a word created from a combination of "tetra" (meaning "four") and his favorite sport, "tennis".
Because the Electronika 60 had no graphical interface, Pajitnov modelled the field and pieces using spaces and brackets[18]: 299 (45 lines of 80 ASCII characters).[13]1:50 Realizing that completed lines filled the screen quickly, Pajitnov decided to delete them, creating a key part of Tetris gameplay.[20] This early version of Tetris had no scoring system and no levels, but its addictive quality distinguished it from the other puzzle games Pajitnov had created.[22] Pajitnov wrote the game using Pascal for the RT-11 operating system on the Electronika 60.
Pajitnov had completed the first playable version of Tetris c. 1985.[23][24] Pajitnov presented Tetris to his colleagues, who quickly became addicted to it.[17]: 87 It permeated the offices within the Academy of Sciences, and within a few weeks it reached every Moscow institute with a computer.[17]: 87 [25]: 9 min A friend of Pajitnov, Vladimir Pokhilko, who requested the game for the Moscow Medical Institute, saw people stop working to play Tetris. Pokhilko eventually banned the game from the Medical Institute to restore productivity.[17]: 87
Pajitnov sought to adapt Tetris to the IBM Personal Computer, which had a higher quality display than the Electronika 60. Pajitnov recruited Vadim Gerasimov, a 16-year-old high school student who was known for his computer skills.[17]: 87 [18]: 300 Pajitnov had met Gerasimov before through a mutual acquaintance, and they had worked together on previous games.[8] Gerasimov adapted Tetris to the IBM PC over the course of a few weeks, incorporating color and a scoreboard.[18]: 300 The PC port was written with Turbo Pascal.[