Captivated, Harry watched as Draco moved with an energy that seemed to sync perfectly to the beat he was creating. With a series of taps sparkling notes spurted forth, then with a twist here or there a rumbling noise would emerge, all deftly layered together as if Draco were some sort of sculptor of sound. He worked with speed and confidence. The mechanics of it all inscrutable, but wonderful. Harry felt himself almost cocooned in the melody.