fountains (or the ground around a fountain), the spandrels of arched doorways, or wall surfaces framed by arches of carved stucco. Simpler checkerboard-like motifs were used as backgrounds for the rosette compositions or to cover other large surfaces. In more modern houses and mansions, even cylindrical pillars were covered in tilework up to the level of the capital. In Morocco today, zellij art form remains one of the hallmarks of Moroccan cultural and artistic identity and continues to be used in modern Moroccan architecture. Fez remains its most important center of production. Workshops in other cities like Meknes, Salé and Marrakesh generally emulate the same style as the craftsmanship of Fez. The exception to this is the city of Tétouan (in northern Morocco), which since the 19th century has hosted its own mosaic zellij industry employing a technique differing from that of Fez. The patterns of traditional zellij are also still used in some Spanish decorative tiles, but in modern Spanish tiles the geometric motifs are simply painted and baked on large tiles rather than formed by mosaic. Fabrication Zellij tiles are first fabricated in glazed squares, typically 10 cm per side, then cut by hand with a small adze-like hammer into a variety of pre-established shapes (usually memorized by rote learning) necessary to form the overall pattern. Although the exact patterns vary from case to case, the underlying principles have been constant for centuries and Moroccan craftsmen are still adept at making them today. The small shapes (cut according to a precise radius gauge) of different colours are then assembled in a geometrical structure as in a puzzle to form the completed mosaic. Uniquely in the city of Tétouan, zellij tiles are cut into the desired shapes before being baked. This results in a harder enamel that lasts longer, but the colours are not as bright and the tile pieces generally do not fit together as tightly as those produced in other cities like Fez. Once baked and cut, the tiles were laid face down on the ground and assembled together into the intended pattern. The back of the tile pieces were coated together with thin layers of plaster or whitewash. Once dry, this coating bonded the tile pieces together into larger panels. In Nasrid tilework the plaster was mixed with threads of esparto grass and cane to provide them with more tensile strength. The panels were then affixed