The Turkmen are a very significant tribe, mostly inhabiting Afghanistan and the former Soviet Republic of Turkmenistan. The Iranian population is limited to an area around Gonbad-e-Kavus (500.000 inhabitants) in the Mazandran Province. The Iranian Turkmens belong to three tribes; the Yomut, the Tekke, and the Atabat. The first two are most famous for their rugs. They were originally nomadic tribes, but most Iranian Turkmens are now settled, although they often have a traditional round tent in a square near their modern brick houses. Turkmen rugs are traditionally made of wool and have a limited range of colours; red, black, and ivory, sometimes mixed with other colours and silk. The typical patterns are geometrical flowers (güls), and octagonal patterns with variations according to tribe. According to tradition, the rugs are made in several sizes, depending on where in the tent they are to be used; as door curtains, bag covers, etc. Very large rugs are sometimes made to order for tribal chiefs.