A circular "cafe wall" optical illusion table

It’s even more obvious from overhead

This table is made of four concentric circles that are actual, true circles, even though our brain processes them as spirals.  It was handmade by Mike Guetta from ExoticTiles in Montreal, Canada. This visual effect is based on the cafe wall optical illusion.

The cafe wall illusion

The actual cafe

The illusion was first observed on an actual cafe wall in Bristol, England, and explained in a paper by Richard L. Gregory and Priscilla Heard in Perception magazine.
Buy a homemade table for your own illusionistic cafe: Cafe Wall Illusion Table, Etsy>>
– See a moving version of the illusion at Cafe Wall Illusion, Michael Bach>>– An interactive version, at IllusionWorks>>– From the Exploratorium>>– Technical explanation of the illusion at Dr. Gregory’s site>>– Found via an entry at Boing Boing: Optical illusion spiral table>>