General Yue Fei, a famous general who fought against the Jin Dynasty in the Southern Song Dynasty, lost his father when he was young and his family was poor. He relied on his mother's sewing subsidies to support the family. He had no money to buy pens, inks, paper and inkstones, so Yue Fei picked up branches and mixed them with sand to learn cultural knowledge and calligraphy. . In addition, there are many great calligraphers who became obsessed with calligraphy, such as the ink-washing pond of Wang Xizhi and his son, and the idiom "three points into the wood". Hope this helps.