and al-Andalus. Some exceptional examples of this pattern from the Marinid period are found in the zellij tilework of the al-Attarine and Bou Inania madrasas in Fez, where greater visual diversity was once again achieved by using large repeating units. In these examples and in others, additional visual diversity was also achieved through the use of colour. By varying the colours of the pieces, different patterns could be highlighted within the same geometric motif. Other types of compositions were also employed, many of them much simpler. Some mosaics were simply composed of coloured squares. One variation of this is a "checkerboard"-like pattern made up of repeating squares/lozenges separated by white strips with eight-pointed stars at their intersections. In the Alhambra of the Nasrids, some zellij motifs were composed of interlacing ribbons or tracery, sometimes as part of a narrow frieze wrapping around doorways or running above larger zellij dadoes. Another motif distinctive to the Alhambra is the so-called "Nasrid bird" (), which is composed of a three-pointed star with curved arms that is repeated in a wheel-like motif. Yet another motif consists of one repeating curvilinear form resembling a double-headed axe, which is found in the Alhambra and is also common in the zellij of Tétouan in Morocco, where it is known in Arabic as the "four hammers" (arba'a matariq). A straight-lined version of this motif, similar to the 12th-century zellij on the minaret of the Kutubiyya Mosque, is also found in the Alhambra, where it is referred to in Spanish as the "bone" (hueso) motif. A darj-wa-ktaf (or sebka) motif is also employed in some Marinid tilework, including examples at the al-Attarine and Bou Inania madrasas. Numerous other tessellated motifs are attested. An Aramco World article about zellij states: An encyclopedia could not contain the full array of complex, often individually varied patterns and the individually shaped, hand-cut tesserae, or furmah, found in zillij work. Star-based patterns are identified by their number of points—'itnashari for 12, 'ishrini for 20, arba' wa 'ishrini for 24 and so on, but they are not necessarily named with exactitude. The so-called khamsini, for 50 points, and mi'ini, for 100, actually consist of 48 and 96 points respectively, because geometry requires that the number of points of any star in this sequence be divisible by six. (There are also sequences based on five and on eight.) Within a single star pattern, variations abound—by the