How fun! I found this while browsing around on shoutwire. Basically because of the way our eyes render colors, they absorb the original image. When a black and white image is then put infront of that, you see the black and white image in complete color until you move your eyes! http://www.johnsadowski.com/big_spanish_castle.html Very Cool!
Heh I saw this on another site a couple of days ago, but still, very nice. Shows the refresh rate of your eyes