I was an undergraduate student of George's many years ago and it's an absolute delight to see these renderings. He used to doodle them on any available surface -- blackboards, notebook paper, napkins, what have you -- often with a fountain pen. He was also big into using computers for visualization and had a number of programs that ran in the CAVE.

Very nice. I've been inspired by the same sources and have always wanted a way to render such drawings for any arbitrary 3D model (e.g. STL file). I've played around with that quite a bit, even recently with LLM assistance, but haven't yet gotten it as good as I want. Eventually...!

The spacing and style of the hand sketched lines are really perfect. Was it hard get such clean drawings, even using principal curvature fields?

Is there a way to hide the menu on mobile? The few pixels I can see do look pretty cool.