In 506 B.C.（the 4th year of Dinggong，Duke of the state of Lu），Confucius visited the Temple of Huangong，Duke of Lu，and saw the tilting containers displayed in the temple as an exhortation.He said to his disciples，"I hear that when the container is empty，it is tilting； when it is properly filled，it is upright and when it is full，it is overflowing."