Zellij (; also spelled zillij or zellige) is a style of mosaic tilework made from individually hand-chiseled tile pieces. The pieces were typically of different colours and fitted together to form various patterns on the basis of tessellations, most notably elaborate Islamic geometric motifs such as radiating star patterns. This form of Islamic art is one of the main characteristics of architecture in the western Islamic world. It is found in the architecture of Morocco, the architecture of Algeria, early Islamic sites in Tunisia, and in the historic monuments of al-Andalus (in the Iberian Peninsula). From the 14th century onwards, zellij became a standard decorative element along lower walls, in fountains and pools, on minarets, and for the paving of floors. After the 15th century the traditional mosaic zellij fell out of fashion in most countries except for Morocco, where it continues to be produced today. Zellij is found in modern buildings making use of traditional designs such as the Hassan II Mosque in Casablanca which adds a new color palette with traditional designs. The influence of zellij patterns was also evident in Spanish tiles produced during the Renaissance period and is seen in some modern imitations painted on square tiles. Name The word zillīj () is derived from the verb zalaja () meaning "to slide," in reference to the smooth, glazed surface of the tiles. The word azulejo in Portuguese and Spanish, referring to a style of painted tile in Portugal and Spain, derives from the word zillīj. In Spain, the mosaic tile technique used in historic Islamic monuments like the Alhambra is also referred to as alicatado, a Spanish word deriving from the Arabic verb qata'a () meaning "to cut". History Origins (10th to 13th centuries) Zellij fragments from al-Mansuriyya (Sabra) in Tunisia, possibly dating from either the mid-10th century Fatimid foundation or from the mid-11th Zirid occupation, suggest that the technique may have developed in the western Islamic world around this period. Georges Marçais argued that these fragments, along with similar decoration found at Mahdia, indicate that the technique likely originated in Ifriqiya and was subsequently exported further west. It was probably inspired or derived from Byzantine mosaics and then adapted by Muslim craftsmen for faience tiles. By the 11th century, the zellij technique had reached a sophisticated level in the western Islamic world, as attested in the elaborate pavements found at Qal'at Bani Hammad in Algeria.