What are the four characters in China's calligraphy?

Dragon and phoenix dance, vigorous and powerful, dragon and snake at the bottom of the pen, Mo Miao at the bottom of the pen, dragon and snake with the same pen, swallowtail silkworm head, hiding the head and protecting the tail, happily sinking, happily quiet, learning graffiti, ups and downs, Ding Zhenkai grass, Ding Zhenyong grass, dragon dancing phoenix, iron painting silver hook, splashing ink dripping wet, full of strength, phoenix floating, dancing dragonfly, phoenix dancing. Strong and powerful, flowing, both rigid and flexible, with a pen like a cloud, a runaway horse, a flying dragon, moving from nothing to nothingness, the world is dry, the thickness is dry, broken and twisted, and the thickness is clear.