Stare for at least 30 seconds at the litte red cross. Then suddenly look at a light surface (like a white wall). You will suddenly see a perfect apparition of Barack Obama! It helps if you blink your eyes really fast.
We call this phenomenon an afterimage. The cells in your eyes are being overstimulated. Normally, your eyes would compensate for it with little movements, but the staring prevents that.
The interesting thing about illusions like this is, that the afterimage seems much more detailed than the original, inverted image.
We call this phenomenon an afterimage. The cells in your eyes are being overstimulated. Normally, your eyes would compensate for it with little movements, but the staring prevents that.
The interesting thing about illusions like this is, that the afterimage seems much more detailed than the original, inverted image.