一叶落知天下秋

Explanation: Leaves from a litter, that the arrival of autumn. Subtle metaphor for individual signs, you can see the whole situation and development trend of the results. 　　Source: "Huai said mountain training," see a leaves were gone with knowledge of the twilight years of age. "Song Tang G," paper record "drawing the number of Chinese poems Shanseng understand six decades, a world known autumn leaves were gone."