During the Eastern Jin Dynasty, the minister Wang Dun had long harbored rebellious ambitions. One day, he dreamt of a single piece of wood piercing the sky, believing that the time was ripe for his grand scheme.

He then consulted Wu Meng, asking if it was feasible to declare himself emperor at that moment. Wu Meng replied, "Adding a horizontal stroke above the character '木' (mù, wood) forms '未' (wèi, not yet). This signifies that although the wood seems to pierce the sky, you cannot act rashly yet, because the Jin dynasty has not yet declined."

Later, Wang Dun's rebellion indeed failed, and he eventually died within his army.