Post #2454887

@pieter@mathstodon.xyz I think I went through a very similar train of thought. Selinger's construction ultimately produces the fractal as a union of disjoint triangles, and you can iteratively descend through levels of substitution, bailing out early if you ever reach a "definitely inside" or "definitely outside" sub-region. But I boringly iterate over ever smaller quadrilaterals, rather than inverse-transforming the sample point relative to fixed shapes (I agree that both directions will probably work fine).