Ceci n'est pas une spirale

This must be one of the most convincing optical illusion I have ever seen.

The image shows an optical illusion that has concentric circles with checker-board patterns between them. The arrangement makes it look as if the circles make a spiral where in fact they are not.
Ceci n'est pas une spirale

Don't know where it originally came from, I found this optical illusion that looks like a spiral on Make's website . They also show a version traced by lines to help convince you that this really is NOT a spiral.

By xorbit, last changed on April 21, 2010 // E-mail to a friend //