I once visited an art exhibition where the theme was art objects that change while being displayed. Once exhibit which I particularly enjoyed was a cassette that was being played, while its outrolled tape was tightend around some bars in the room. So the tape slowly grinded down and changed the (cryptic) sound that was being played. It was a super cool idea, which also played with the experience of an unwound cassette tape, that everyone (who is a bit older) knows.