Alexey Pajitnov used Pascal to program the Elektronika 60 version of Tetris. He wrote the original game while working at the Soviet Academy of Sciences’ Dorodnitsyn Computing Center, using the machine’s RT-11 operating system.
The Elektronika 60 had no modern raster-graphics display, so the first Tetris represented its falling pieces with text characters such as brackets and spaces. Pajitnov originally explored a computer adaptation of pentomino puzzles, then simplified the idea to seven tetromino shapes because they made a more manageable game.
Pascal is sometimes confused with the language used for later ports. Pajitnov, Dmitry Pavlovsky, and Vadim Gerasimov used Turbo Pascal when adapting Tetris for the IBM PC, but that was a subsequent version. The original Elektronika 60 program is also often described as a 1984 creation, although commonly cited accounts place its completion in 1985.