Furthermore, in terms of types, circular seals are generally single-character or double-character, and the author's surname or font size was engraved in ancient times. Irregular shapes are also used for seal cutting. Generally, there is no name engraved on it, and more famous sentences or the author's research number are engraved. Therefore, most stamps and complimentary stamps exist in the form of collecting stamps (that is, if someone gets a work he likes very much, he can stamp it or attach a stamp to prove that this person has collected this work. )。 However, Fang Zhang is mostly a work chapter, which exists to show his identity.