This act acquaints us with the magical, fanciful world of the fairies, so Shakespeare uses poetry to convey the enchanting quality of their realm. A fairy speaks with Puck in rhyming couplets: lines end on rhyming words, such as "green" and "queen," "favors" and "savors."
Shakespeare also uses vivid imagery to conjure the world of the fairies. Imagery allows us to imagine we can see, hear, touch, smell or taste what is going on in a scene. Shakespeare describes how Titania loves the young Indian boy she has adopted. She "crowns him with flowers." This is an image because can visualize her doing this. We also learn that Titania and Oberon are fighting over the boy. Shakespeare also helps us visualize the king and queen of the fairies formerly meeting in harmony near clear fountains or under clear skies: "By fountain clear or spangled starlight sheen." This helps us better understand how their current disharmony causes storms and crop failures. We see too that the "elves" of the kingdom "creep into acorn cups" to hide from the king and queen's anger. We can picture an elf hiding in a an acorn cup.This image communicates how tiny these fairies are. This is important, because, obviously, real actors, not tiny beings, would play these parts on stage.
Titania speaks in metaphor when she says to Oberon that his idea that she is seeing other men is "the forgeries of jealousy." A metaphor compares two things without using like or as. A forged signature is a false signature and forged money is fake money, so she is comparing Oberon's idea of her having affairs to a false or fake object. Oberon is speaking false words.