The difficulty increases in direct proportion to the number of crossbars being used. Cloth woven with one crossbar is only one layer thick. With two crossbars you can weave inner and outer layers, but it takes four crossbars to weave a small pattern, eight for a medium-sized pattern and twelve for a large pattern.
花紋的困難度與杆數成正比：一杆織出來的布只有一層，兩杆才能織出裡外兩層，織小花要用四杆，中花要八杆，大花則要用到十二杆。