The blue and the green optical illustion.
You see embedded spirals, right, of green, pinkish-orange, and blue? Incredibly, the green and the blue spirals are the same color. At first I thought Richard was pulling our collective legs, being a trickster of high magnitude. So I loaded the image in Photoshop and examined the two spirals. In the two squares displayed, the one on the left is colored using the same color from the blue spiral, and on the right using the green spiral.
