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?
When California video game developers Spectrum Holobyte produced Tetris for the Apple IIGS and the Mac, they had to find something suitably Soviet for the theme music.
They settled on an old Russian folk song named "Korobeiniki" (meaning Peddler) which has a much longer history than the game itself. The song was based on a poem from 1861. More importantly, it's famous for its slowly increasing tempo, which fit this stressful puzzle game perfectly.
Many gamers who have had "Type A" stuck in their heads for decades will be surprised to learn the song has lyrics. Korobeiniki tells the story of a traveling peddler wooing a young woman as they haggle over the price of some goods (as you can guess, there are a few double entendres involved).
"Katya is haggling with care,/ She is afraid to pay too much,/ A lad is kissing his lass,/ Asking her to raise the price." Who would have guessed that that was playing in the background to all of our Tetris games?
Of course there's another reason the Game Boy version of the song was such an earworm. It was re-arranged by one of Nintendo's best composers, Hirozaku Tanaka, who also did the music for Metroid, Super Mario Land and Dr. Mario.
Share this story if you still have "Type A" stuck in your head!