Using your computer, click on this image and print out what you see. Using scissors, carefully cut out the disk. Pierce the disk in the center with a thumbtack. Spin the disk. What do you see?

As the Benham disk spins, we see spinning black and white lines as well as a faint hint of color within the lines. The colors are an illusion caused by the way our eyes respond to the light reflecting off the Behnam disk. If you happen to see brown in the spinning disk, then color receptors in our eyes are responding in an unusual way to allow you perceive brown as being there. No brown color is actually being creating, you just see it that way.

See how many different colors you can find in your spinning Benham Disk. Many different combinations are possible.