Day 15 challenges us to handle very large overlapping areas.
Part A tempts us into brute-forcing a solution. It’s doable, and it works fine. Part B is not amenable to brute-force, though there is a “trick”, which in retrospect I think is pretty obvious. (It’s so obvious in retrospect it’s hard to think of it as a “trick”. But it took me 30min of noodling to get there, so.)
I think there are potentially non-brute-force solutions for Part A that are effective solutions for part B as well, involving compressing space into intervals.
There’s not a lot of “motion” in this problem, though we could illustrate the search. Still, it’s interesting to see the problem space visually.
I have a working prototype of stacking ultra-high-framerate renderings to produce usable GIFs. The motion seems a lot smoother to me (rendering at 1000fps and then blurring together 50 frames), but there’s still some work to do. Stay tuned. Or not. You do you.