Symmetries of Islamic Geometrical Patterns

In 711 an army of Arabs and Berbers from North Africa, united by their faith in Islam, crossed the Strait of Gibraltar and arrived on the Iberian Peninsula. In less than a decade the Muslims brought most of the peninsula under their domination; they called the Iberian lands they controlled al-Andalus. Although the borders of al-Andalus shifted over the centuries, the Muslims remained a powerful force on the peninsula for almost eight hundred years, until 1492, when they were expelled by Ferdinand and Isabella. …