Try to keep these balls in the center of your vision, they'll keep moving!

What: This isn’t the first time we’ve got some Akiyosi Kitaoka [1] on the site, and it won’t be the last. This is a classic example of illusory motion, where the balls appear to be moving in the peripherals of your vision, but are in fact completely still.

How To: Mix up the colors, sizes, and spacing to see how it affects the illusion. I found that the illusion is strongest when the colors are contrasting, and the balls not super large, although I could see it there

Explain it: Another Illusory Moment, and as always the Wikipedia [2] has a great description of the current thought process. I’ve also mentioned within the illusory motion beans illusion how this is working (as I can understand it), your brain is used to perceiving things that fade one way or the other as moving, and the contrasting colors here are causing a collusion of the senses.

Cites and Extras:

I've researched these optical illusions in my spare time but am clearly not any kind of expert and my explainations are pretty smooth brained, if you find something mis-cited, earlier examples, or general mistakes please new let me know via, be kind!