"Leak mark" is a metaphor for the vivid lines of works and the vivid aesthetic feeling of calligraphy lines, which has been favored by calligraphers and has continued to this day.
The metaphor of "painting sand with a cone" makes it hidden and easy to paint. When the pen is used, it is often intended to pass through the back of the paper.
Source:
"Tapered sand painting" comes from Yan Zhenqing's "Return to Zhang Changsheng's brushwork" and "leakage mark" comes from the skull's "Sacrifice to a Nephew"
Extension:
Yan Zhenqing's brushwork effect has the shape of "drawing sand with a cone", Huai Su has the trace of "leaking marks" and Chu Suiliang has the shape of "Yin Yinni", all of which are metaphors of vivid lines of works and vivid aesthetic feeling of calligraphy lines, and are favored by calligraphers and continue to this day.
Among them, the source of the leakage is Huai Su and his brother, who often accept children's brushwork. Tong said, "Call Tong privately and say,' I feel strange when I fly alone in the sand'. The sage of grass is here." Yan Zhenqing said, "Is the teacher complacent? Sue said, "I have seen many strange peaks in Xia Yun, so I need to learn from them often. Its pleasure is like a bird flying out of the forest and a snake jumping into the grass. It is natural to encounter the road to the wall again. " Zhen Qing said, "Why is it like a leak?" Su Qi shook hands with the public and said, "I see." ("shihuaisu and Yan Zhenqing on cursive script")
In addition, Yan Zhenqing said in "Returning Zhang Changsheng's brushwork": "I use sharp edges (on the shaping) to paint and write books. Its strength and danger are obvious and attractive. From then on, I learned to use a pen to "draw sand with a cone" to hide the front and draw calmly. When I use a pen, I often want it to pass through the back of the paper. This is extremely successful. "