This might be one of the most satisfying optical illusions I've ever seen. Not only does it look slinkily 3D printed, but once you get the hang of it, it switches from pointing outwards to inwards with the flick of your focus. I can imagine having a physical version of this image, and pushing it in and out to transform in the way the illusion works.
The r/opticalillusions subreddit is equally as transfixed, with comments flooding in praising the "fantastic find" (and only a couple calling it a "rainbow nipple". Yes, yes I see it, too). Take a look below.
