Drat. It seemed so simple. Go back to the UK, meet up with family and friends and show them a few photos. And then, when we were looking at pictures of some Chinese buildings, the question.
"Just why do Chinese buildings have curved roofs?"
Seems simple doesn't it. Some research on the web confirms (!) that they do indeed have curved roofs (e.g. "The roof of a typical Chinese building is curved") but no-one seems fit to put forward a theory as to why that actually would be.
It's annoying because it's a simple question and apart from a vague attempt at "something to ward off evil spirits" I had to admit defeat.
Any ideas out there?