Copied out of Jean Marie Castera’s ‘Arabesques’:
Could do it better if I was using a ruler and not half watching the Apprentice.
The point is – if you are at all interested in the construction and art of zelij, you have to have this book:
Arabesques: Decorative Art in Morocco, by Jean-Marie Castera.
It’s a quite pricey, but worth every single penny.
Zelij - a Morrocan artform 