Yes, I got completely sidetracked by one concept in my explorations yesterday. I didn’t try half the things I wanted to do. Here is the concept as a diamond center and then as a square (approximate) center.
The diamond center with trimmings
Another trial, this time with the trimming as shown in the first of those photos above. Sorry about the shadows; I forgot to practice one of the few key ideas I know about photography in these pictures.
A fill based on the squarer version of the concept.