In a carnival sideshow I saw as a kid there was an Aquarium Man with fishes swimming in his head. You stood in a queue, and, when you came up to him, he would look at you to show you that his eyes were normal and that there were no tricks involved, then he would blink once or twice and open his eyes as wide as possible and the different fishes would float by. There were goldfish and tropical fish with long feathery tendrils in many colors, and there were even tiny sharks and swordfish. Then the Aquarium Man would shut his eyes and open them again and show you that his eyes were perfectly normal and he would wink at you and that was it–next! I went through the line many times to convince myself that I was actually witnessing this wonder, and I began to ask the Aquarium Man questions–How did you get them inside? Where do your eyes go? Does it hurt? Do they live on your brain? It's a trick, isn't it, isn't it? But the Aquarium Man would only wink and say, Next!