Chris! Love it! I made something along these lines (I had seen it in an old Popular Science) on my laser out of colored plexi for a window shade but I did the iris like a real camera lens with overlapping pieces. I had all kinds of problems with rubbing and scratching of the plastic so you could hardly see out after while. I like this design with the pieces butting up so much better! Very ingenious - as always!
I have been bragging up your Bot in a Box to people when they come to look at mine.
Thanks!
Mike