HT: Richard Wiseman.
This is a lovely effect!
First of all, tickets for the next Edinburgh Secret Society event will go on sale at 10am today. But be quick, because we expect to sell out quickly. Details here.
Second, I haven’t seen this illusion before, and it is great. When the paper squares are on the screen the lines look like they form a square moving in a circular motion. However, remove them and a very different picture emerges.