Optical Illusion: Negative Woman

Want to give this a try? You'll be amazed! Stare at the red dot on this woman's nose for thirty seconds. Then, look over at a blank white space (a piece of paper or an empty browser tab will do). You'll see the "correct" version of the image.  Here's how it works: stare long enough at an object and the eye's photoreceptors (particularly the color-sensitive cone cells seen on her nose) lose sensitivity from overstimulation. Divert the eyes to a blank space,
and the surrounding cone cells send out a much stronger signal. The brain interprets this discrepancy as looking at the precise opposite colors, in what is known as a 'negative afterimage.'