What is the fable written by Wang Xizhi?

Lin chi bu bu bu

There was an allusion in the Eastern Jin Dynasty that Wang Xizhi admired Zhang Zhi's calligraphy when he was young. In order to write well, he practiced calligraphy by the pool every day, and finally washed the ink and dyed the water black.

Quitting means giving up and stopping.

To cling to the pool now is to do one thing persistently.