That's what it looks like to me, as well. That was actually the first thing that came to mind, that it looked like the warning symbol for radiation.

Edited to add:

I hit enter to soon. I meant to add that even though that pattern looks like the radiation warning symbol, I don't think it has anything to do with radiation. It's just similar to common aerial search and rescue patterns, which is what I think it is.

That's what it looks like to me, as well. That was actually the first thing that came to mind, that it looked like the warning symbol for radiation.