at the iconic cubo prism with hybrid path.
I didn't want to render longer than a day and chose 500 samples/frame which was probably no good idea because there is some visible noise from fireflies, also because OIDN was at 70%.
300 frames in 24h on Ryzen 2700X + RTX 2070.
Glass material is 80% dispersion + 20% roughness, a big and a small point light at the same location for lighting, no background.
In order to make looping possible after a 180° turn I had to mirror the ground plane material and even to remodel the prism which was not 100% symmetric causing a shift in caustic patterns between 0° and 180°