It's kind of like a visual analog of a Shepard's tone. Those things are kind of like the dress that some people saw as one color and other people saw as another. Shepard's tone would be worth googling. Some people find them soothing. I just think they're a trip.
The background appears to me moving upwards while the foreground appears to be moving both downwards and sideways. Your eyes trying to follow multiple opposing directions at once is so disorienting it basically puts your brain on tiltt. Would be way worse if it took up your whole field of vision.
