I'm surprised this hasn't been mentioned yet: https://xkcd.com/724/ https://xkcd.com/724/ and an implementation here: https://www.kongregate.com/games/banthar/h

I'm surprised this hasn't been mentioned yet: https://xkcd.com/724/ https://xkcd.com/724/ and an implementation here: https://www.kongregate.com/games/banthar/hell-tetris https://www.kongregate.com/games/banthar/hell-tetris