How to model this pillow?

[Duopoli]

Hi! I would like to know what are some of the ways I could model this particular pillow of mine. I know that there are a lot of tutorials online teaching you how to make pillows, but they always end up with a different shape from this one.

As you can see from the photo, this one has this… Frill? I don’t know what to call it. But it has this detail that goes around the sides and on top. This detail has a wave pattern along its edges. I tried highlighting it in the image below:

This detail is not “loose”. If you look at the picture, you can see that it’s sewn together, meaning it doesn’t “puff up” when the pillow in inside the cover.

So, again, what are some of the ways I could model this pillow while keeping this detail?

[thorn]

Start with the pillow, select the outer perimeter of edges.

Shift D to duplicate that edge. Then hotkey P, separate the selection. Now we have a new object, for the frill.

Select the edge border of the frill object, fill the face. Now the frill edge can be dragged a bit to make it a bit irregular in shape to the pillow if desired.

[Duopoli]

Thank you very much!