Li Shu painted charcoal
To describe a situation in which people are in dire straits. [source] Liu Yuanhai's biography in the book of Jin states: "Li Shu's accusations were made when he painted charcoal."
Idioms and allusions
[source] Liu Yuanhai's biography in the book of Jin states: "Li Shu's accusations were made when he painted charcoal." [example] with the momentum of the whole country, your majesty can not resist the enemy, abandon the country and flee far away. Bi Yuan, Qing Dynasty, volume 94 of Xu Zi Zhi Tong Jian
Discrimination of words
The subject predicate type is used as the object and has a derogatory meaning
Li Shu painted charcoal
praise a person before everybody - féng rén shuō xiàng