I know a bit of magic so when I see a card trick I can usually figure out what the trick is behind it. But a while ago this guy showed me a trick where you take two cards, fold each of them, one hotdog and one hamburger, both so that the back of the card faces out. He then put the hot dog one inside the hamburger one so one end was sticking out. He asked me to push the card inside so that the other end would stick out. When I did, the other end was inside out. I've made a crude illustration to show you what I'm talking about. Obviously the card was ripped and twisted at the center, but I have no idea how he'd pull that off discretely, especially since I watched him do the whole thing. Any ideas?