A Pen created at CodePen.io. You can find this one at https://codepen.io/robdimarzo/pen/NMBBNP.

 As your eyes focus on different parts of the visual, the pattern in your periphery appear to undulate. But is anything actually moving? 

This idea is not my own-- it's a recreation of some illusory motion examples I found online. Illusory Motion is a type of optical illusion based on the works of Japanese psychologist Akiyoshi Kitaoka. If you like Animal Collective, you might notice this type of graphic from their album "Merriweather Post Pavillion".
