Is used:

In matter-of-fact styles (scientific prose) - to show the semantic equality of the parts

In belles-lettres / publicistic style - an emotive function

- a means of comparing or confronting facts

Married men have wives, and don’t seem to want them. Single fellows have no wives, and do itch to obtain them.

Chiasmus

Greek - “letter X” = Chi (“crossing”) reversed parallelism SPO – OPS

I looked at the gun and the gun looked at me. (R.Chandler )

There are wives who are in trouble over their husbands. There are husbands who are in trouble over their wives. (A.Christie)

In titles : r. Jacobson “The Poetry of Grammar and the Grammar of Poetry”.

• witticisms (play on words):

Soldiers face powder, girls powder faces.

A handsome man kisses misses, an ugly one misses kisses.