Jerome H sent me this great animated Ebbinghaus illusion…..amazingly the orange circle stays the same size!
I think it originates here, along with lots of other cool stuff.
UPDATE: Re the origin, of this, Stan noted:
One week ago at the Vision Sciences Society meeting in Florida was the annual visual illusions Hollywood style competition of the 10 best illusions of the year. They will be featured in Scientific American Mind. It already has a Wikipedia entry at http://en.wikipedia.org/wiki/Ebbinghaus_illusion. The last sentence of that entry is:
“The winner of the 2014 Best Illusion of the Year Contest, submitted by Christopher D. Blair, Gideon P. Caplovitz, and Ryan E.B. Mruczek, of the University of Nevada Reno, animated the Ebbinghaus illusion, putting it in motion.”