the fabric. A number of different tools may be used to shear the wool depending on how the rug is trimmed as the weaving progresses or when the rug is complete. Often in Chinese rugs the yarn is trimmed after completion and the trimming is slanted where the color changes, giving an embossed three-dimensional effect. Knots Persian carpets are mainly woven with two different knots: The symmetrical Turkish or "Giordes" knot, also used in Turkey, the Caucasus, East Turkmenistan, and some Turkish and Kurdish areas of Iran, and the asymmetrical Persian, or Senneh knot, also used in India, Turkey, Pakistan, China, and Egypt. The term "Senneh knot" is somewhat misleading, as rugs are woven with symmetric knots in the town of Senneh. To tie a symmetric knot, the yarn is passed between two adjacent warps, brought back under one, wrapped around both forming a collar, then pulled through the center so that both ends emerge between the warps. The asymmetric knot is tied by wrapping the yarn around only one warp, then the thread is passed behind the adjacent warp so that it divides the two ends of the yarn. The Persian knot may open on the left or the right. The asymmetric knot allows to produce more fluent, often curvilinear designs, while more bold, rectilinear designs may use the symmetric knot. As exemplified by Senneh rugs with their elaborate designs woven with symmetric knots, the quality of the design depends more on the weaver's skills, than on the type of knot which is used. Another knot frequently used in Persian carpets is the Jufti knot, which is tied around four warps instead of two. A serviceable carpet can be made with jufti knots, and jufti knots are sometimes used in large single-colour areas of a rug, for example in the field, to save on material. However, as carpets woven wholly or partly with the jufti knot need only half the amount of pile yarn compared to traditionally woven carpets, their pile is less resistant to wear, and these rugs do not last as long. Flat-woven carpets Flat woven carpets are given their colour and pattern from the weft which is tightly intertwined with the warp. Rather than an actual pile, the foundation of these rugs gives them their design. The weft is woven between the warp until a new colour is needed, it is then looped back and knotted