If you grew up in the '80s or '90s, you can probably still see the iconic Tetris blocks falling when you close your eyes.
The classic puzzle game of matching blocks and disappearing lines has a long and strange history that stretches throughout the final years of the Cold War. Tetris was originally created by Alexey Pajitnov, an artificial intelligence researcher at Moscow's Soviet Academy of Sciences.
Pajitnov was working at the Academy's Computer Center in 1984, and would test the new hardware's strength by designing simple games. His creations were shared between departments, and the most popular one of all was Tetris.
After workers in other offices got a hold of the game it spread throughout Moscow, and then to the rest of Europe, where it was picked up by western game developers. While Pajitnov didn't get credit or compensation for his work at first, the game became an instant hit on our side of the Iron Curtain.
And while the game was addictive, one of the most memorable features of Tetris was the music. The classic Tetris theme, named "Type A" on the Game Boy version, is so notoriously catchy that you're probably humming it right now.
But did you know the song actually has lyrics?