In my novel I'm working on a little problem: how could two men be each other's uncles? Hisae and I were on the U2 line on Sunday when we saw these two men on the platform:
Hisae said "Do you think they're father and son?" and I replied "No, I think they're each other's uncles." We then spent a long time working out whether this was possible, and how. It's actually a really difficult problem, and I'd like to hear your answers. I now have two ways they could be each other's uncles, but one only works if one of the men is the other's great uncle.