Okay, this is my first slip-up post. In the movie X-Men, when Erik and Sabretooth are walking to the cell that's holding Senator Kelly. As they go, the metal planks are pulled up for them to walk on. If you look in the background near the bottom of the screen. You see the shadow from the planks along the stone. But as more of the planks are added, the shadow doesn't change. It's very obvious. Take a look!