The observant will note the doubly nested closure
It's me again! I'm sure you'd rather not hear any more comments from revdiablo, but I'd like to point out something I observed in another post in this thread.
This is not a double closure, it's just a single closure that uses anonymous subroutines. The inner subroutines do not close around anything, because they are not stored anywhere. They are created and destroyed each time they are used. They never get a chance to create a closure.
Update: I guess this really depends on your definition of "closure". As I said in a reply to our good friend AnonyMonk, I don't generally use the hyper-technical definition that a closure is "anything that closes around a lexical", because that's true of any subroutine that is in a lexical environment. Which, if you're using lexicals in Perl, is all of them.
I prefer to think of closures as subroutines that actually use that lexical environment for more than one invocation. I think this captures the meaning most people think of, as well as a meaning that is actually useful for something.