Udakarahadasutta
“Cattārome, bhikkhave, udakarahadā. Katame cattāro? Uttāno gambhīrobhāso, gambhīro uttānobhāso, uttāno uttānobhāso, gambhīro gambhīrobhāso— Ime kho, bhikkhave, cattāro udakarahadā. Evamevaṁ kho, bhikkhave, cattāro udakarahadūpamā puggalā santo saṁvijjamānā lokasmiṁ. Katame cattāro? Uttāno gambhīrobhāso, gambhīro uttānobhāso, uttāno uttānobhāso, gambhīro gambhīrobhāso.
Lakes
“Mendicants, there are these four lakes. What four? One is shallow but appears deep, one is deep but appears shallow, one is shallow and appears shallow, and one is deep and appears deep. These are the four lakes. In the same way, these four individuals similar to lakes are found in the world. What four? One is shallow but appears deep, one is deep but appears shallow, one is shallow and appears shallow, and one is deep and appears deep.