A simile succeeds best when it is a converted metaphor, for it is possible to say that a shield is like the drinking bowl of Ares, or that a ruin is like a house in rags, and to say that Niceratus is like a Philoctetes stung by Pratys the simile made by Thrasymachus when he saw Niceratus, who had been beaten by Pratys in a recitation competition, still going about unkempt and unwashed.