Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3224264.

optical illusion - a tracking skull

"murray" looks like following you with his eyes and head. See in the Animation bellow (it takes some seconds to load). The whole thing is a pretty simple principle but looks impressive. The skull can be fixed on the wall like a picture or be placed somewhere on a Desk. I made also a stand with the possibility to illuminate the skull directly by a LED, this amplifies the effect immensely.

Scale both models to the desired size and print easily (printing the skull upright will probably give the better results)