A slogan: a tree can't be a forest.

No monofilament forms a line, and no tree forms a forest.

At first, "one line can't make a line" and "one tree can't make a forest" both had their own origins. Because these two sentences are similar in form and meaning, they are dual and easy to understand, so they were put together later.

"Monofilament is not a line" Source: Yuan Anonymous's "Chain Meter" The second fold: "Say that monofilament is not a line, I hope you will be round when the moon is missing."

Explanation of "Single filament is not in a line": Single filament is not in a line. It is difficult to get things done because one's strength is thin.

"One tree does not make a forest" Source: Han Cuijian's "Da Zhi": "The tree is high and shady, and one tree does not make a forest."

"A tree can't be a forest" explanation: A tree can't be a forest. Metaphor personal strength is limited, can't do great things.