Zeppo and Wolf, of course I was merely offering an alternate explanation. I wanted to point out that the "shadow and light" explanation isnt necessarily solid, open-shut case kinda thing. I dont know what you captured, but it was interesting nonetheless.
Oh, I agree, the shadow/light idea is just that, an idea..
Truth be known, I would much prefer it was more...and like you say, at the very least, it is an interesting picture no matter what the cause.
(Or what is it)