“Ripening Apple,” Friend, Oct. 1994, 35
Ripening Apple
Color the apple green and the leaf blue. Under good lighting, stare at the center of the green apple while you count slowly to thirty. Without blinking, quickly look at the empty box next to it. You should see a ripe red apple with a yellow leaf. This is called an after-image. If it doesn’t work for you, you may have to stare at the apple longer.
