I ended up implementing a variation of that algorithm for my game jam entry, Fire Rescue Chopper: [Announcement] MakeCode Arcade Mini Game Jam #2 - Submission thread! - #7 by kwx
My version adds a black outline at ridges for a slightly cel-shaded look, and I think the old 8-bit LucasArts game “Rescue on Fractalus” did something similar when drawing mountain outlines. It’s currently not particularly optimized, so it works ok-ish on a sufficiently fast system in the simulator, but would need converting to fixed-point math for running on hardware. I don’t have my PyGamer with me to test, but I expect frame rates well below 1fps on that…