How many different 'tetriminos' are used in the video game "Tetris"

"Tetris" is a tile-matching puzzle video game originally designed and programmed by Soviet Russian software engineer Alexey Pajitnov. The first playable version was completed on June 6, 1984, while he was working for the Dorodnitsyn Computing Centre of the Academy of Science of the Soviet Union in Moscow. He derived its name from combining the Greek numerical prefix tetra- (the falling pieces contain 4 segments) and tennis, Pajitnov's favorite sport. The name is also used in-game to refer to the play where four lines are cleared at once

The pieces on which the game of Tetris is based around are called 'tetriminos'. Pajitnov's original version for the Electronika 60 computer used green brackets to represent the blocks that make up 'tetriminos'. The final seven 'tetriminos' used in the video game were each given a different color. Versions of Tetris on the original Game Boy/Game Boy Color and on most dedicated handheld games use monochrome or grayscale graphics, but most popular versions use a separate color for each distinct shape.