Below are several examples of various literary devices found in Chapter 20 of Harper Lee's novel, To Kill a Mockingbird.
ALLUSION & METAPHOR. During his final summation in the Tom Robinson trial, Atticus makes a statement that can serve as both an allusion and a metaphor: "... a pauper the equal of a Rockefeller, the stupid man the equal of an Einstein."
ALLEGORY. Much of Atticus's summation would qualify as an allegory, especially the paragraph concerning the "integrity of our courts and in the jury system--"
SIMILE. Atticus compares a falsehood to a Negro's skin: "... a lie as black as Tom Robinson's skin."
SYMBOLISM. When Atticus removes his coat and loosens his tie, he is ridding himself of the symbols of authority, reducing himsef deliberately to the status of the common man--the men of the jury to whom he is addressing.
PERSONIFICATION. The Coca-Cola is given human characteristics when Dolphus Raymond tells Dill to "Take a good sip, it'll quieten you." Atticus's busy briefcase takes a breather as "it rested beside his chair."
PERSONA. Dolphus Raymond has created an alternate version of himself, the supposedly misguided, drunken man who drinks from a bottle in a sack, weaving and staggering and living with the Negroes. In fact, he is sober and quite clear-thinking.
IRONY. Atticus points out the irony of Bob Ewell swearing out a warrant with his left hand (Atticus had previously proved that a left hand had struck Mayella, and Tom's left hand was crippled) while Tom Robinson took "the oath with the only good hand which he possesses--his right hand."
HAMARTIA. Tom Robinson's classic flaw was that he had the nerve to "feel sorry" for a white woman.