Boards
Optical Illusions
Just saw this http://thedailywh.at/2011/08/16/optical-illusion-of-the-day-7/ - and whilst it isn't my favourite, it is pretty good (takes a bit to get going). How do they do that?
I'm not sure what my favourite optical illusion is. What's yours? Ideally link without an explanation so people can reply guessing how it's done.