There is no crossing and inclination, and geese don't fly in pairs.

There is no horizontal or oblique, that is to say, the horizontal of calligraphy is basically not straight, and there is a certain slope of low left and high right, even for regular script.

Yan Bu Qi Fei's statement comes from official script. The ancients regarded the proportion of foot-picking in horizontal painting of official script (including pressure) as dovetail. It is appropriate to press the foot once for a word, and it will be the same if there are two strokes, and the font will be delayed. "Wild geese don't fly in pairs" means that feet can't be used any more. In fact, this principle is also used in other books, in order to avoid overlapping strokes and inflexibility.