Trying to make this corner detail

I found this chair I liked online and I’m trying to make the corner detail of the seat cushion. It looks like the fabric is folded in a way that makes two creases.

Attached is my pathetic attempt to try to make this detail.

corner detail.blend (829.2 KB)

Please let me know if there is a better way to do this.

Thanks!

For realistic cloth, use the cloth modifier.