seeing around corners

I’ve been trying desperately to determine why this technique for “reconstructing a scene from a different vantage point”: is useful (as opposed to just a neat trick). It’s probably a great technique for use with live-action-plus-CG films, but I’m at a loss to find any other application.

Still, it reminds me of a discussion I had with Adam Houston a while back about using a regular wall as a mirror by reconstructing the paths of all the light rays hitting it. They aren’t quite doing that, but they can still see the back face of a playing card using a similar trick. (View the video at the bottom to see the trick in action.)