Issues while creating the pattern for the edge surface of the ring

I am trying to get the edge of the ring look like on the image but can not quite get it .
Honestly can not imagine how to do it because the surfaces seem to merge together.
I would so appreciate if you could give me some hints.
Thank you.



Post a .3dm file with what you have done so.

Here is the file)
22.09.3dm (1.1 MB)