Dots Optical Illusion

Michael Borcherds had the idea that this suddenly popular optical illusion could make an interesting applet, and wondered if the color of the dots would make a difference. So here's my attempt! I had to make it a guessing game. I thought about a timer, but wasn't sure if that would be good.[br][br]What do you think about the color of the dots?

Information: Dots Optical Illusion