> I don’t believe I’ve ever seen shape utilized in generated ASCII art, and I think that’s because it’s not really obvious how to consider shape when building an ASCII renderer.

Not to take away from this truly amazing write-up (wow), but there's at least one generator that uses shape:

https://meatfighter.com/ascii-silhouettify/

See particularly the image right above where it says "Note how the algorithm selects the largest characters that fit within the outlines of each colored region."

There's also a description at the bottom of how its algorithm works, if anyone wants to compare.