Consider a constructed comparison:
Statement A: “The brave man does not fear an enemy.”
Statement B: “He is a lion in battle.”
Both describe courage, but the first is a simple report and the second a conventional simile. The overlap proves neither verbal copying nor theft of a rare idea.
Now imagine that a writer invents a very unusual sequence of images, and another reproduces their structure and distinctive inference. In that case the resemblance is no longer simply a shared theme of courage; it concerns a particular artistic construction.