2. Hard pen calligraphy is divided into Fang Bi and round pen, and Fang Bi and round pen are the stippling forms of pens. Fang Bi has a square outline and a round pen has a circular outline. However, a square and a circle are relative. When Fang Bi is magnified thousands of times, it will certainly bring some circular radians. When the round pen is narrowed, it will feel like a square. They are unity of opposites. It is not advisable to have no pen at all, but it is also unreasonable to blindly pursue pen and Fang Bi.