Is THAT it! I've let online pp., esp. https://www.chaptercheats.com/cheat/iphone-ipod/400025/Virtual-Villagers-Origins-2/hint/101484/, mislead me.

love: Yes, or I couldn't've done puzzle 12.
littlecates: Well, the first link is, despite the typos.
ladiestorm: Yes, counting same way, across then down. I'd read about the waterwheel, but not as a numbered puzzle.