There is a place (or was) in the Berkely hills that you could interact physically with the music and direct it according to the motions of your body and/or a wand you held. Music was incoming somehow, and somehow you redirected its output according to the way you play with the wand. Its intent. It was/is some kind of stage with sensors. I dont know specifically how it works, I just read about it, but I want to try it out some day.