Today I hit a milestone. And what a nice one. I can remove Beethoven's eyebrows. More importantly I have a big chunk of one of my test cases done and working: A very naive decimation algorithm (collapse shortest edge), and I've done it badly. Mostly because every time I would change an element of an array in an imperative language I have to copy the damn thing, and once that's out of the way there's a load of O(n) searches on the arrays due to my equally naive mesh representation (vertex array, polygons and edges reference indices of the vertex array) but the really good news is I know how to improve it

Ok so it's about 4 minutes of CPU time to go from the mesh on the left to the one on the right. Impressively bad huh?