Some folks can see through the "eyeballs."

To try it, place your own eyes directly in front of the orbs, and look straight through them with each eye, as if they were your own eyeballs. The two images will merge into one, and the result will be in 3D. - (It might help to start off with your nose almost touching the screen, then back off a bit, far enough to bring them into focus.)

- This is a technical exercise to demonstrate the validity of optics using Bryce3D -