During the Tang Dynasty, Prime Minister Zhang, despite having poor handwriting, particularly loved writing in cursive script. Instead of following conventional cursive rules, he invented his own style, making his characters appear like flying dragons and coiling snakes, which rendered them illegible to others.

This caused much trouble for his nephew, who helped him copy manuscripts.

One day, while copying a poem for Zhang, his nephew encountered a character he couldn't decipher and went to ask him. Zhang himself couldn't recognize the character either, yet he scolded his nephew for not asking him sooner.