"Oriental rug" is a general term for handwoven rugs and carpets (rugs larger than 9' x 12') that originate in a large geographic area once generalized by westerners as "oriental" but now often referred to as the Islamic world. These areas include Persia (Iran), the Caucasus, Central Asia and Turkey and correspond with sheep grazing land that provides wool fleece for spinning and weaving. Oriental rugs are functional but also have symbolic uses. Tribal rugs woven on portable hand looms are Oriental, but "fine" Oriental rugs are woven on stationary, upright vertical looms often located in urban areas and sometimes known as "city rugs". The finest antique Oriental rugs (older than 100 years) were made in Persia. Three structural elements create an Oriental rug: warp, weft and pile. The warp runs the length of the carpet and emerges at each end as a fringe. The weft is yarn fiber woven with or knotted to the warp fibers. The weft is sheared or cut to form a pile. A skilled weaver may average 5,000 knots per day and spend up to a year completing a room-sized rug with a complex pattern. Less complex designs require less time. Small rugs are often the work of one weaver; larger rugs are usually a team effort. Most Oriental carpets have densities of 100 knots per square inch (known as kpsi) but the count is higher for fine rugs. In the 21st century a rug is termed "Oriental" based on how it is made – design plus hand weaving and knotting techniques – rather than where it is made. Countries where contemporary, new Oriental rugs are made include India, Afghanistan, Pakistan and Nepal.