An oldie, but a goodie. Found this optical illusion on an old CDR that I was about to bin.
Your eyes are making it move. To test this, stare at one spot for a couple seconds and everything will stop moving. Or look at the black centre of each circle and it will stop moving. But move your eyes to the next black center and the previous will move after you take your eyes away from it…. Weird hey.
And strangley depending on your eyes it bleeds out over the right hand nav!