dimensional masks are worn by evil foreigners, demons, and witches, and masks that cover the entire head are used to portray animals. Like the 'cham, the morality play is performed outdoors, with the audience, except for the specially seated lamas and nobles, standing or sitting on the ground around the performing area.The morality plays are performed (acting) for profit by groups consisting of lay men and women, and some have Buddhist monks or nuns as members. These troupes are generally associated with a given locale, such as a village or a monastery; however, they often travel to give performances on special occasions, transporting their wardrobe and stage props with them. In time, four of the most popular troupes were required by the Tibetan government to perform plays at the summer palace of the Dalai Lama. These performances were obligatory as a kind of taxation. There are still several of the a-che-lha-mo troupes to be found among the Tibetan refugees in Nepal and India, where their performances are in popular demand.The a-che-lha-mo did not spread from Tibet into other parts of Central Asia until the 19th century. According to tradition, the Mongolian lama Noyan Hutuqtu (1803–56) studied a-che-lha-mo as performed in the Kokonor (Tsinghai) region of northeastern Tibet and then introduced his own adaptations of it at Tulgatu-yin keyid, his own monastery near the village of Saynshand, in Mongolia. For the first time, in 1832, he produced a repertoire of four plays, and their performance required 17 full days. The four plays were based on the textual biographies of the historical Buddha, the Indian Buddhist Teacher Atīśa, the revered Tibetan hermit-poet Mi-la Ras-pa, and the fabulous “Moon-cuckoo” (Saran-u Kökügen-ü Namtar), a mystical story of a pious prince who became a cuckoo bird living in the forest.Noyan Hutuqtu's productions differed from the usual performance of a-che-lha-mo in certain respects. His repertoire did not include any of the plays traditional in Tibet. His actors, unlike those of a-che-lha-mo, wore no masks; instead they painted their faces, a makeup technique associated with Chinese opera. Whereas a-che-lha-mo is usually performed outdoors in the Himalayan regions, Noyan Hutuqtu had a special theatre constructed near his monastery. It was a three-sided, two-storied, mud-brick building with two stage floors; thus, two scenes could be performed at the same time. The upper stage represented the sky, the lower one the earth. There were stage exits on both sides and trap doors in the floor.The first Mongolian actors were called schabi, or disciples, of the lama Noyan Hutuqtu. These men and women formed a regular troupe and were invited all over Mongolia to perform.Among the peoples of Central Asia, folk dancing occurs as a form of entertainment at social occasions, such as festivals, weddings, and other celebrations, and private parties. Often impromptu, folk dances are sometimes performed without the accompaniment of musical instruments, and the performers rely on singing and footwork to maintain the rhythm.Formalized folk dance does not appear to have evolved among nomadic peoples of the steppe and desert regions, but such dances did develop among the sedentary agriculturists, particularly in the Himalayan regions, where troupes of amateur performers were formed for local entertainment. Some dances were performed by a group of men and women forming a circle; in others, the dancers faced each other in lines. The dance steps and body movement were performed according to a stylized routine, and the rhythmic beat was accented by a measured stamp of the foot.Turrell V. WylieVisual artsPrehistoric culturesThe earliest artifacts discovered in Central Asia were found in Siberia and western Turkistan and are from about the 13th millennium BC. During the millennia that followed, migrants entered the region from various directions, regardless of the geographic obstacles they encountered. As a result, some of their artifacts correspond with those produced at a similar stage of development in more western areas;