The illusion consists of a patterned set of blue and red circles, set out like a target against a black background. It's meant to appear in 3D (when of course it is completely flat). It's a version of an illusion I've seen before that's very similar but completely plain - and that one always causes division too. Some people blame astigmatism for their failure to see the illusion's effect while others have no explanation.
Unlike most scooter and motorcycle riders, summer has always been the season I ride the least. I've blamed the heat. Or the laziness I feel whenever the temperature rises into the upper 70s. Whatever it is I seem to come back to life when I can step outside in the morning with the temperature at 50. This summer was no different. But a few things were stirred into the mix