The author's source is Tang's Broken Wang Xizhi: "Wang Xizhi's book is willing to be published, cut by workers, and the pen is incisive." There was a famous calligrapher named Wang Xizhi in the Jin Dynasty.
Once, Wang Xizhi wrote on the blackboard. After he finished writing, the workers tried to erase the handwriting, but they couldn't erase it for a long time, so they had to scrape it with a knife! I didn't expect to scrape three minutes thick wood to wipe the handwriting clean. It turns out that Wang Xizhi's handwriting has penetrated into the wood three points thick! This shows how deep Wang Xizhi's writing skills are!
Later, someone changed Wang Xizhi's words into the idiom "get to the point" to describe a person's words, speech or performance? Sorry!