Rotating brush is a special calligraphy skill, which requires superb skills and experience to master.
Moreover, the process of turning over the pen to write is very complicated, which requires repeated practice and exploration.
Therefore, calligraphers who can skillfully use flip pens are rare.
Although Mi Fei is not famous for turning the pen, he occasionally uses this skill in his calligraphy works. For example, some words on the map of Jiu Si are written by flipping the brush.
But on the whole, the proportion of Mi Fei's calligraphy using flip-flops is not high.