Our senses aren't perfect! If your eyes follow the movement of the rotating pink dot, you will only see one color, pink. If you stare at the black + in the center, the moving dot turns to green. Now, concentrate on the black + in the center of the picture. After a short period of time, all the pink dots will slowly disappear, and you will only see a green dot rotating if you're lucky! It's amazing how our brain works. There really is no green dot, and the pink ones really don't disappear. This should be proof enough, we don't always see what we think we see. Stare at the four black dots in the center of the image for 30 - 60 seconds. Then quickly close your eyes and look at something bright (like a lamp or a window with sunlight coming through it). You should see a white circle with an image inside it. Going Up or Down? For this optical illusion to work, stare at the center crosshairs and move your head in and out from the screen. Sometimes when you just look to the side or relax your eyes a bit, you'll notice the spiral moving. I'm sure this has all been posted before, but I couldn't help myself. Post some cool ones you have, if you wish.