What is the unique style of Yang Heng, a seal writer and official calligrapher in Yuan Dynasty?

Yang Heng (1234 ~ 1299) was born in Yanzhou (now Yanzhou, Shandong). Yuan Shizu Middle School was appointed as Professor of Jining Road in the fourth year (1263), and was later called the proofreader of Taishi Museum. In the thirty-first year of Zhiyuan (1294), I visited the Ombudsman. After Chengzong acceded to the throne, he was promoted to minister and less supervisor. Rehearse "Great Unity" and return to China after the rank is full.

Yang Heng was a representative calligrapher who was proficient in ancient Chinese and was good at seal script in the early Yuan Dynasty. "History of Yuan Dynasty" contains: "(Heng) is well-read and proficient in the study of seal calligraphy. He has written six books series, Six Books Rejecting the Source, Calligraphy, etc., which generally publicizes Xu Shen's theory and deepens its meaning, and all of them survive in the world." The three books of Yuan collected in the Palace Museum are masterpieces of seal script, official script and regular script written by Yang Heng, Xiao Shuangdou and Zhao Mengkui. At the beginning is Yang's representative work "Wuyi Pian", with nearly 600 words. It is seamless and unified. It is different from the "graceful and smooth" characteristics of seal script since Qin and Han Dynasties. Instead, he adopted the brushwork of "pouring leeks" which combined Cao and Li Si's seal script with ancient Chinese, and learned to "curse Chu Wen".