The action puzzle game Tetris the Grand Master first appeared in game arcades in August 1998, and became a beloved game for gamers as a Tetris game packed with addictive elements. Then ...

Taking this to the extreme, [numeric] abused the user-defined characters to write a tiny game of Tetris that would run in the 10×16 frame that you get when you combine four characters together.

The more you move it, the game thinks you have more trouble with that certain piece, and will dish out more of them. You can exploit this every time you get a Tetris (Long "I" shape) piece ...