Years ago (we’re talking decades) I ran into a small program that randomly generated raytraced images (think transparent orbs, lens flares, reflection etc), suitable for saving as wallpapers. It was a C/C++ program that ran on Linux. I’ve long since lost the name and the source code, and I wonder if there’s anything like that out there now?
POV-Ray, perhaps? You give it a scene description text file and it will render a raytraced image of the scene for you. You’d need to find or write an appropriate scene description though for what you want to randomize.
Thanks for the suggestion, but that’s not the one.