It looks suspiciously as if they did something sensible and coherent for the vertices of the original mesh and then had some interpolation accident happen on the rest. There's a clear pattern there, so one should be able to reverse engineer what they did, but I'd need some strong motivation to attempt that kind of thing, like - I don't know - Alison Brie promising to teach me wrestling moves.

-- I'm not mad at you, just Westphalian.