These boys are not brothers, they are friends

It's really interesting how Rosetta Stone uses visual learning to teach language, and I'm often really impressed by their way of coming up with suitable imagery to teach sort of complicated concepts.

This one is "These boys are not brothers, they are friends", from my Chinese language version:


I thought the use of race difference was a bit surprising, but then I thought about it. How else might this concept be illustrated? I couldn't think of a better way, but does anyone have any ideas?