What are the artistic features of Three Graves Monument in calligraphy?

"Three Graves Monument" was written in the second year of Dali, and the inscription was Li Zhuan Shu. The original stone no longer exists, and the stone tablet preserved in Xi 'an Forest of Steles was re-carved in the Song Dynasty. ***23 lines with 20 words each. In the Qing Dynasty, he said in the Yihetuan Selling Summer Stories: "Since the Han and Qin Dynasties, Li has been called the first hand. The' Three Graves Monument' we saw today is so dense and vivid that it is really difficult for anyone to compare with him. "