Here's a llama. There's a llama. If you have ever heard the , Llama Song , you are probably familiar with having a song stuck in your head that just won't go away. What is the scientific name for this?
This is an optical illusion that I first saw as part of a kit of magic tricks that I received as a present when I was young. The kit was designed for children, so most of the "tricks" were things that did not take a lot of skill. Like many other magic tricks, this one relies on science instead of sleight of hand.