The cones of yarn are wound over a drum (known as a swift or mill) and a warp (lengthwise threads) is made for weaving. This can be a complicated process depending on the intricacy of the pattern in the finished fabric. Precise lengths of different coloured yarn may be required in a single vertical thread and up to 2000 threads may be required for a width of fabric. These are checked by hand and must all be held in an exact order to ensure accurate and uniform patterns and designs.