^Propagation of light waves. Now if you think of just how fast
   light moves, this is absolutely stunning. (I had to mute the
   music - not my style) - but watch how light will make an object
   completely glow for just a moment as if it's lit up from the
   inside -- stunning. And how you can see an image slowly appear
   on a mirror, or bounce off an object and onto the surrounding
   walls.^