A traditional yurt (from the Turkic languages) or ger (Mongolian) is a portable, round tent covered with skins or felt and used as a dwelling by nomads in the steppes of Central Asia. The structure comprises an angled assembly or latticework of pieces of wood or bamboo for walls, a door frame, ribs (poles, rafters), and a wheel (crown, compression ring) possibly steam-bent. The roof structure is often self-supporting, but large yurts may have interior posts supporting the crown.