[Tunabrain]

Ah, you're most likely talking about Wenzel Jakob's wonderful 2D tool for demonstrating Manifold Walks.

Wenzel was actually one of my thesis advisors, and his tool was the inspiration behind this project. :) I was writing an implementation of Manifold Walks out of personal interest and reproduced his 2D tool for debugging purposes. Eventually I realized that caustics in 2D actually look kinda neat, so I spent some time doing research and then fleshed it out into this article + demo.

[tgb]

Yes, it was definitely Wenzel Jakob's work. Do you know if he has that demo available online? I couldn't find it on his webpage.

[Tunabrain]

I don't think he ever released it. It would definitely be very cool to play around with though.