Interactive visualization of Kerr spherical photon orbits (2016) (duetosymmetry.com)

Animated this would make a reasonably nice addition to XScreenSaver

Here's some videos I did a few years ago. Program source on Github.

https://www.youtube.com/playlist?list=PLvGnzGhIWTGRuIsHzDLde...

Thank you for sharing this...it so awesome to see threejs.org for understanding educational concepts so easily. Kudos!!!