2. Huai Su (737-799), born in Lingling, Yongzhou (now Lingling, Hunan), was a calligrapher in the Tang Dynasty. Huai Su's calligraphy is characterized by cursive script. When he was writing a book, his pen was like a hairspring, and the circle rotated, as if he were scared by a snake, like a storm, his font was crazy and angry, and his lines excited a meteor. A strong thought and feeling of "going crazy to despise the world and gaining true knowledge from drunkenness" flowed out in this line of work. Because his calligraphy is bold and unrestrained, he is known as "wild grass". Wild Grass was born in the Tang Dynasty, which embodies the passion and vitality of the prosperous Tang culture.