Carpets woven by nomadic tribes across the Middle East, Central Asia, and North Africa, who move with their flocks through spring, summer and fall and settle in winter to weave. Working on compact portable looms, they typically make small pieces (for example 4 x 6 or 5 x 7 ft, about 1.2 x 1.8 or 1.5 x 2.1 m), sometimes runners, using woolA natural animal fiber used for the pile, and in some rugs also the foundation, of high-quality rugs. It is durable, resilient, stain resistant and flame resistant, feels soft and cushioned underfoot, insulates against cold, and takes up dye readily and holds it for many years. It also traps dust particles, which helps reduce allergic reactions. Quality depends above all on where the sheep graze: high-elevation pastures and good feed give thicker, oilier wool, with Manchester, New Zealand and Ghazni wools the best-known prized examples. Early-spring shearing and hand spinning (finer, softer thread than machine spinning) improve it further, while thin, dry wool from dead sheep goes into cheaper rugs. from their own flocks, often for both foundation and pileThe surface of a rug or carpet, made of upright fibers in cut tufts or loops. In a hand-knotted rug it is formed by the cut ends of thousands of wool or silk knots tied onto the warp row by row, trimmed lightly during weaving and given its final height by shearing at finishing. Pile thickness, measured from the back of the rug to the top of the pile, typically runs from low, about 1/8 to 1/4 inch (3 to 6 mm), to high, about 1/2 to 5/8 inch (13 to 16 mm). Fine, dense designs are cut short to keep the pattern sharp; higher pile suits traffic and heavy furniture, lower pile suits door clearance and humid rooms., traditionally dyed with local plants. The bold, mostly geometric designs are passed down through generations without written patterns and sometimes echo city rugs. Unlike city or workshop rugs, they often show asymmetry, color variation and patterns that do not resolve neatly at the corners.