Synesthesia is a figure of speech (as well as a medical condition) that combines in a single expression images related to two or more different senses. Bottom's speeches and lines continuously have examples of this literary term, such as, when he says,
I see a voice! Now will I to the chink,
To spy and I can hear my Thisby's face. (5.1.193)
What is Shakespeare's purpose in using synesthesia at this point in the play?