An iTunes playlist of rough drafts contains 4412 tracks; the most recent of them, something called “Jubilant Hair Sad,” was made just the night before. “I can’t remember what it is,” he says. We listen to it for a moment: slow string pads—the kernel of an idea, maybe, but not much more. “That’s not very interesting,” he says, turning it off. Perhaps part of genius is knowing when to give up on a ho-hum idea and move on.