I'm new to Pico-8. I've been learning from the great carts very talented ppl publish here at Pico-8 BBS. I've just seen a demo doing pretty colorful spirals and wanted to test myself doing something similar in a per pixel color fashion.
The code is a pretty slow unoptimized version without look up tables or palette reordering, but, hey, it works!
Use left/right/up/down to tweak parameters.