This is the first time i'v seen this one and I thought it was awesome! Try it out.. http://www.johnsadowski.com/big_spanish_castle.html eric
The negative colors leave a negative impression on your eyes, resulting in the positive color look of the original picture. clever.
if you keep staring at the dot the color stays but if you move off it a bit it goes back too black an white. That is a really sweet illusion