The debate continues. Is the now-famous dress white and gold, or black and blue? The folks over at XKCD showed how people see either version.The dress color is the same in both panels--only the background has changed.
Believe it or not, the green and the blue spirals are actually the same color. At first glance, our brain assumes that the orange and magenta stripes are continuous--but they're not. So the magenta stripes make the green look blue. Read more about it here.
The boxes marked A and B are the exact same shade. Your mind recognizes a familiar checkerboard pattern, and a shadow from the cylinder, and fills it in so that it makes "sense." Still don't believe it? Here's a cheat sheet.
Look at the woman dancing in the center. Which direction do you see her spinning? The version on the left shows how she could be spinning clockwise, and the version on the right shows how she could be spinning counterclockwise. All of this and more can be seen in the new movie, "Step Up 6: Ambiguity."