To Do and Notice: Stare at the picture of black lines. What do you see?

What's Going On: Afterimages of the alternating black and white lines seem to create a shimmering effect when viewed with the eye. Eye movements are responsible for the shimmering that you see. When your eye moves back and forth naturally across this image, the evenly spaced lines are superimposed on the back of the eye causing the shimmering effect. Amazing!