What makes the Spinning Rainbow Circles illusion work.

An explaination of what part of the Spinning Rainbow Circles illusion makes the rings appear to move and change size. EDIT: I obviously did not go deep enough into the explanation of the cognitive effect of the coloured edges in my video and I now wish I had, so I will try to explain it a bit better here. When I watched the clip originally I was really confused how the illusory motion was being triggered and once I worked out what part of the animation was causing it, I was just glad to know. Since I already understood how illusory motion worked I didnt feel the need to go into the details. I should have. I will redo this video with a audio narrative and going into illusory motion. Regarding illusory motion; If you picture how a movie works, we see a series of frames with slight differences between each frame. As we watch, one frame with a person in one position and in the next frame they are in a slightly different position and so on. Our eye sees each of the individual frames but as it would overload if it had to process all that data, it kind of doesnt bother to. In fact our brain (being the clever little lump of water and fat that it is) keeps the original image and processes the changes to smooth it all out. We see it as fluid motion. In fact our brain goes a step further and actually anticipates the changes to a degree. In the case of the rotating rainbow rings, as a colour (eg the dark blue) is passing a point on the ring it is trailed behind by a thin edge of the same blue after it has passed, our brain pics up this change, interprets and smooths it out as if the whole blue section moved slightly in that direction. Now that shouldnt in etself produce the illusion of motion as much as a flickering but our helpful brain anticipates that that movement is going to continue and so we percieve it to do so. It does adjust but essentially keeps falling for the same trick over and over and we really percieve that there is movement there.