In thinking of light, if we can think about what it can do, and what it is, by thinking about itself, not about what we wanted it to do for other things, because again we've used light as people might be used, in the sense that we use it to light paintings. We use it to light so that we can read. We don't really pay much attention to the light itself. And so turning that and letting light and sound speak for itself is that you figure out these different relationships and rules.