Yan-ti characters are full of strokes and dense in structure, which is difficult to express with a pen, especially for beginners. Some hard-pen calligraphers have also made some explorations in this respect and gained some experience. In the past, they occasionally saw "Yan-style hard pen calligraphy works" in pen calligraphy competitions, but at present, due to my shallow knowledge, I have never seen or heard of a hard pen calligrapher who specializes in Yan-style regular script. Hard pen calligraphers are not mature here, not to mention it is unrealistic for high school students to learn pen calligraphy. Basic exercises are enough to show the characteristics of pens.