"The original version, launched on June 6, 1984, was only 10
levels long because that was all the Elektronika's memory could
handle. Inspired by the classic riddles and puzzles Pajitnov loved
as a child, the game was so addictive he couldn't even stop playing
long enough to finish programming it. "The program wasn't
complicated," he told the Guardian. "There was no scoring, no
levels. But I started playing and I couldn't stop." The game became
known as Tetris, a combination of the Greek prefix tetra and
Pajitnov's favorite sport, tennis." Google's logo is
Tetris-ized today-- ed.