What metaphors are used in Why The Classics by Zbigniew Herbert?

In Lines 7 and 8, Herbert uses the line break to create tension. For instance, "the episode is like a pin" leaves the reader waiting for the conclusion of the metaphor "in a forest," which makes clear that Thucydides's failing is insignificant when considered in the context of his many victories. Placing the conclusion of the metaphor on the next line helps to sustain tension in the poem.