Need help figuring out the stitching on a rice pack! Sewing Machines Parts and Sales in Los Angeles

I’m trying to make a rice hot/cold pack that wraps around the neck. I found this old etsy store that doesn’t sell anymore, but I like their design. However, they never show the whole thing laid flat, and I’m having a hard time figuring out the pattern of the stitches to make the pockets; especially to make the collar around the neck lay better. Here are more pictures.

I think that the two outside columns are a quadrilateral, equilateral triangle, and a mirrored quadrilateral. The top of the middle column looks like a square, and I think the middle might be too. However, I can’t figure out what the pattern to make the collar is.

I want to make it as functional as possible, so if any of you have good visual-spacial skills, I’d like some help!