What are the artistic features of Magu Mountain Xiantan in calligraphy?

Magu Mountain Xiantan was written in Dali for six years. He once said: "The beauty of God is far away, and it is the best in Yan Shu's stele." Kang Youwei also thinks that this position is the most difficult for Yan Shu. There is also a small printed book, antique and dense. The fine print edition is the most precious edition in Cheng Nan.