Balance & Opposition
Juxtaposition
Placing things side by side so the reader can compare them. The relationship may remain unstated.
"The apparition of these faces in the crowd; / Petals on a wet, black bough." — Pound
Don't confuse it with Antithesis. Antithesis states its contrast in balanced grammar; juxtaposition just sets the two things down and walks away.
Examples
At the palace, dinner was served on gold. Outside the gate, a child searched the bins.
The adjacent scenes invite a comparison between wealth and hunger without explaining it.
The rest of the family
Antithesis Parallelism Isocolon Chiasmus Antimetabole Oxymoron Paradox