Advent of Optics: Day 1

Since I'm releasing a book on practical lenses and optics later this month I thought it would be fun to do a few of this year's Advent of Code puzzles using optics as much as possible! I'm not sure how many I'll do, or even if any problems will yield interesting solutions with optics, but there's no harm trying! The goal is to use optics for as much of the solution as possible, even if it's awkwar