Daniel Ruiz Aguilera tweeted this amazing image that he made in GeoGebra from the Qarawiyyin Mosque in Fez, Morocco. ([url=https://tube.geogebra.org/m/cJaAevax]His sketch[/url].) I was interested in both how this design was made and how it might generalize, so I gave it a go. As near as I can figure, the entire design depends only on the choice of the width of the bands! (Point C in this sketch.) There are so many beautiful structures that combine geometry and artistic choice in this piece that dates back to the 9th century CE. What a masterpiece![br][br]More about the [url=http://www.muslimheritage.com/article/al-qarawiyyin-mosque-and-university]mosque and university[/url].