In which script did Xiao Zhuan evolve?

After Qin Shihuang unified the six countries (22 1 year ago), official documents were distributed to the whole country. Li Si, then prime minister, called for a unified script. On the one hand, he abolished the ancient Chinese and regional traditional characters used by the six countries. On the other hand, he simplified and transformed the common script of Qin State (handed down from Zhou Xuanwang, which belongs to Da Zhuan) into Xiao Zhuan. For the sake of distinction, predecessors called Shu Zhuan Da Zhuan and Qin Zhuan Xiao Zhuan.