Turntables are great for turning recorded art into something you can enjoy, but here's a rig that harnesses two turntables to create a kind of visual music.
The turntables are connected to a pen through a pantograph type mechanism, that uses the rotating platters to move the pen. By setting the turntables to rotate at slightly different speeds, the pantograph moves across the paper in a predictable but ever changing pattern. The resulting geometric designs remind of what I would get from a Spirograph back when I was a kid, but this system doesn't require you to move the whole apparatus along.
For what it's worth, designer Robert Howsare says that the drawings "serve as a marker of temporality," whatever that means. I just think they look cool.