It's been a hard week to find time for AOC -- my grandma was diagnosed with Covid, my freelance work is picking up and... Christmas shopping. So I'm going to have to skip day 17 for now.

Day 17 seems to be a 3D version of day 11 -- with an unknown outer boundary. My plan is to start with my day 11 code and work from there. I'm not sure when I'll get to this (maybe after Christmas), but when I do I'll post my thoughts/solution.