Whose "Wild Grass" is famous for its calligraphy among the three wonders of the Tang Dynasty?

Zhang Xu, Zhang Xu (675- 750) was born in Wuxian County (now Suzhou, Jiangsu Province) in the Tang Dynasty, and his ancestral home was Hehe. During Kaiyuan and Tianbao years, he served as the prefect of Changshu County, and Jin Wu has a long history. Known as cursive script, it dances with Li Bai's poems and Pei Jian, which is called "Three Musts" [1]. Poetry is also unique, famous for its seven wonders, tied with Li Bai and He Wei. Together with He, Zhang and Bao Rong, they are called "four sons of Wuzhong". Calligraphy is as famous as Huai Su. Li Zhimin, a pioneer and professor of Peking University, commented: "Zhang Xu realized the wonderland from' solitary crown and self-vibration, flying sand and stones' and the land of returning to Xiang from his sword dance. It is precisely because of taking nature as a teacher that Mo Chi became a master of weeds. "