Far out stuff. What you see against the white background is a bunch of "rotating snakes" that are produced by a visual effect called peripheral drift. As your eyes scan the image, the circles appear to rotate in a snake-like manner. This is caused by the nature of our jittery visual system and how our brain processes contrasting colours.
A Japanese psychologist (Akiyoshi Kitaoka) designed this version of the illusion. I don't know why exactly he decided to do it, but I like how it demonstrates that there are minute aspects of our sensory and perceptual systems that are not readily available to our conscious awareness or control.
How do you stop the rotating effect? Simply focus on the centre point of a single image and fixate on it. If you move your gaze then the effect will reappear. There are better versions online that demonstrate the effect more strongly. See resources below
I found this swirling demonstration at Science World, which is like a nexus of mind-bending information.
Thank you for spinning this way.
Rotating Snakes
https://remosince1988.com/en-ca/blogs/stories/rotating-snakes
Rotating Snakes illusion
https://michaelbach.de/ot/mot-snakes/
Rotating Snakes Illusion—Quantitative Analysis Reveals a Region in Luminance Space With Opposite Illusory Rotation
https://pmc.ncbi.nlm.nih.gov/articles/PMC5308384/
Photograph by 
