I guess. It’s from a necropolis from Morocco, apparently (according to Eric Broug’s book). Fairly simple design, with nested octagons and lots of 45 degree angles:
I added some ‘linker’ octagons in-between the main ones.
Tried out just using watercolour pencils, in the hope that it would be easy and quick:
However, it ends up being very uneven and required a lot of adjustment. Might have been better if I used dilute paint to smooth out the pencil? Not sure.
The final product is on Etsy