Rhapsody in Chess
This dream was such a beautiful synthesis of ideas...
I discover that if you take the two-piano version of Gershwin's Rhapsody in Blue, send it as it's being played to a computer, and somehow execute it, it turns out to be a ingeniously obfuscated algorithm for playing chess. The notes played by each pianist determine the moves made by each side. I spend a while pondering the notes and how they affect the game, and come to the conclusion that Gershwin was the most brilliant hacker of all time.
So suddenly I'm in my piano teacher's studio, with the two pianos back to back and a chess board floating above them. I begin to play the Rhapsody with (or maybe against) her. As we play, the pieces begin to move. My piano teacher can't play chess, but she can sure play Rhapsody in Blue. I begin to hit wrong notes, and my pieces make tactical errors correspondingly, while hers make powerful moves that get her ahead. I play more determinedly and manage to keep my pieces in a good position, but as the piece enters one of its false finales it becomes clear that she will win. The famous seventh chord at the end of the piece is the move that makes checkmate. The chord still echoes in my mind as I wake up.