Benham's Top

Just Imagine Our Eyes Can Deceive Us ! Here is one of those classic visual illusions where we see things that are not there. In famous Benham's top, staggered partial arcs in plain black and white painted on an half black-half white background produces weak flickering color when rotated. No body knows exactly why this happens. Read the Wikipedia article this illusion's_top. I could see light blue and sort of flickering brown when the disk is rotated. Also try varying the speed the speed of the wheel.
What will happen if we reverse the direction of the wheel(top) ? It is very easy to do in Geogebra. If some body needs help please mail me @