Problem: https://adventofcode.com/2023/day/18 Solution: https://github.com/jonathanpaulson/AdventOfCode/blob/master/2023/18.py I wasn't able to solve part 2 without looking at other people's solutions. Pick's theorem (to reduce the problem to finding perimeter and area) and Green's theorem (to compute the area) combine to provide a very elegant solution IMO.