Wow, I love these comments.
re: clone dot comment: I hadn't thought about this torus example! I would need 3 clones, interesting! I like this point you're making.
I was on the fence about the clone dot because it feels kind-of magic-y and less like "there's just a point moving around" from a programming perspective.
re: circular RP2 interactive comment: I also played around with this circulation around the edge of the circle lol. Yea, I kind of know what you mean about the path dependence. If it wasn't path dependent, then I would have a continuous map f: Screen Plane -> Disk, probably such that f(Disk) = Disk, is there a map like that?
And whoa!! This post about hysterisis is super cool. I love how I can see that the space of these points joined by slack is parameterized by a rhombus. Also how the space is like two lines (vertical sides of the rhombus) connected by a line at each corresponding point and how the connecting lines don't connect to eachother.
re: 3D: you're right. I will do it. I'm gonna continue on my 2D journey for a bit more tho, because if I do 3D I will want to add point picking and interaction and I think I want to do raytracing to avoid triangle artifacts.
re: wacky puzzle: had to think about this a bit. Is this space equivalent to an infinitely tall cylinder? Let theta be the angle of a point on the cylinder and h be its height; the corresponding line is perpendicular to the vector, in polar coords (h, 2*theta).
edit: no, this is really wrong lol. I was thinking about how from each line through the origin there's a real line worth of lines parallel to it.
edit2: found this
https://math.stackexchange.com/questions/1848739/a-topology-on-the-set-of-lines/1848770#1848770.
and I see that I was on the right track that locally it looks like each point is on a circle and a line, but I was missing the global twist in the space.