Trying to Find a (Military?) Pocket Pattern

For a while now I've been looking around trying to find a pattern for an arm pocket. Not just any arm pocket, it's a certain type of pocket... From what I can tell it looks like a modified military flightsuit arm pocket, and I thought that if I could find a pattern for the military pocket I could easily modify it into the pattern I need, but I haven't had any luck finding any such pattern to use.

I'm not entirely sure what the military version of the pocket is called... I think it's called a "pencil pocket" or a "pen pocket", but I'm not positive on that. I'll post some pictures below of the style of pattern I'm looking for... These pictures are of the military pocket, not the modified version I'll use for my costume.

The pocket itself looks to be a fairly simple design. My biggest question is that the pocket looks like it can expand out on the bottom, and I was hoping to find a pattern that would show me how to do that (and a pattern just to make the pocket itself, just to be on the safe side).

Has anyone seen a pattern like this? Does anyone know where I might be able to find one? Any help would be appreciated.

Thank you!

You just add a triangle on the right side and bottom that join at the bottom right corner.
It's 1" deep.

A gusseted pocket? That's what the technique? Interesting. Never knew that.

I don't quite understand your pattern, Division 6... But I'll show it to the person helping me with the sewing of the soft gods... She might understand it better than I do. I'm better with the hard goods.

Does that triangular piece only go on the far side of the pocket opposite from the zipper (and it looks like the bottom), or does it go on the side near the zipper as well?

It's only part way on the bottom.
I'll see about getting batteries for my camera and take a few pix for you.

Here's some pix.
As you can see there is just the corner folded and stitched to make the expansion.

Alrighty, thanks. I'll take a good long look at the pictures and see if I can't figure it out.