Once again, it's time for the Best Illusion of the Year contest, sponsored by the Vision Sciences Society.
The top prize went to this video, made by Jun Ono, Akiyasu Tomoeda and Kokichi Sugihara of Meiji University.
This illusion concerns apparent rotation generated by pure translation. Square patterns consisting of four segments appear to rotate when they move straightly at a constant speed across the grid background. More surprisingly, the rotations in opposite directions can be generated by exactly the same square patterns. This illusion might be explained by well-known inchworm illusion; inchworm illusion arises at the four segments one after another resulting in the impression of rotation. This illusion is new in the sense that the rotation is generated by pure
Full disclosure, it took me a bit of staring to see all the rotation patterns. You can judge for yourself.
I loved the second prize winner, by Arthur Shapiro and Alex Rose-Henig from American University, but unfortunately I could not embed it here. Check it out and be prepared to spend some time playing with it.
Finally, here's one I liked by Guy Wallis and David Lloyd from the University of Queensland.
You can see the other finalists here.