Understanding Defensive Diagrams - symbol meaning?

[BKL]

I was wondering if someone could help with the meaning of some of the defensive playcalling symbols, in particular:
(1) position with a small square attached (zone, man?)
(2) position with a small circle attached (zone, man?)
(3) Position with single circle around it
(4) Position with double circle around it
(5) Zig zag line connected to a position

I might be missing some, but these are those I remember. Thanks!

[ZootMurph]

1) A square is man coverage. The game doesn't specify who that player covers, which is a problem I have and have posted under the More Defense thread.
2) Small circle attached is zone, showing where the player will play his zone.
5) The zig zag connected to a circle is a deep zone.
3) Position with a single circle is, I THINK, sitting in a zone in that area the player is set up. Not moving to a zone area, but playing zone where he is.
4) I don't remember seeing a position with 2 circles, so I wouldn't know what that is.

A position connected to an arrow is a pass rush on the defensive line, or a blitz for other position.
I've also seen a position that looks like they are blocking on defense. I honestly don't know what that means.