Metaphor: Captivity
When Peniculus enters the stage, he addresses the audience and talks with them about a philosophical matter, namely how to keep a man captive and chained without actually chaining the actual person. Peniculus talks about the actual chains a criminal may be forced to wear or the way a person may feel chained to a certain place or object. The chains are thus used here as a metaphor for captivity: both the one resulting from crime and the unnatural and destructive attachment a person may feel towards something or someone.
Simile: Like the sea
When Menaechmus II and his servant arrive in Epidamnus, the servant is trying to convince his master to give up his search for his long-lost twin brother. The two have been searching for Menaechmus for six years without finding anything about him. The servant compares himself and his master with the sea, surrounding an island from every side. Through this comparison, Messenio wants to highlight how they searched already every island and how he believes that they should give up because he is sure they are not going to find the lost twin.
Metaphor: A ship heading towards destruction
After Menaechmus II agrees to go with Erotium to her house and send Messenio to take care of their luggage, Messenio looks at his master and compares him with a ship heading towards destruction, towards becoming a wreck: "The pirate ship has got the pinnace steered straight on the rocks!" (75). This comparison is important because it shows Messenio's belief that vice, e.g. in the form of prostitution, can destroy a person’s life.
Metaphor: Story pouring out
The speaker in the prologue uses a metaphor to explain how he's told a bit of the background necessary for the story but now plans to tell the rest: "I've given you now of the argument merely the preface; / And next the plot I'll generously pour out / Not merely by peck or bushel, but by the whole barn" (59). The listener/reader can imagine a few grains falling out, soon to be followed by a generous pour of an entire barn's worth of grain, which suggests just how fast and furious the next five acts are going to be.
Metaphor: Vices of Epidamnus
Messenio warns his master after hearing Erotium invite him into her house, "Why, these are just falling leaves; stay here a couple of days, and there'll be trees falling on you" (73). Imagining the first callings of Erotium as simple leaves compared to the heavy weight of crashing trees allows the audience/reader to see just how perilous the situation might be in Epidamnus for the unwary traveler.
