A strange little side quest
The rules may be simple on screen, but the backstory around Card Sort is anything but tiny. The name Tetris combines a reference to four-square pieces with Pajitnov's interest in tennis. The same trail leads to another fact: Atari's Gran Trak 10 from 1974 is recognized as the first arcade racing video game. That gives Card Sort a little more company than it first appears to have.