Udakarahadasutta untranslated

Udakarahadasutta. There are four kinds of sheets of water: (1) Flat (uttāna) but deep in appearance (obhāsa); (2) deep but flat in appearance; (3) flat and flat in appearance; (4) deep and deep in appearance.

So, also, there are four classes of people: handsome in appearance but shallow in mind; not handsome in appearance but deep in knowledge; neither handsome nor wise; both handsome and wise (AN.ii.105-6).