Ya, I was a bit careless with the docs on this part because it's a private function, but I should update them to make sure they're accurate and clear. The translational part of the affine is still linear so calling this matrix `lin` is not completely accurate either. `affine[:3, :3]` is the scale, rotate, sheer part, maybe I could call it the "multiplicative part"... any other suggestions I can't think of anything better right now?