The common combination pen in calligraphy aims to prevent the physical phenomenon that when the paper is put down, the hair goes straight out and straight in, and the brush is twisted because of the thread.
Generally speaking, the strokes of a running script will have different forms according to the starting position of the next stroke. If the next stroke is on the top and the hook is upward, an attached hook will be formed, and a stroke will be left on the upper right, with the hook facing the upper right, forming a folded two strokes or one stroke (which can be real or imaginary), that is, two strokes or three strokes will be formed.