Consecutive phrases or verses with the same construction, so that the reader compares what changes from one to the next.
In Othello
She loved me for the dangers I had passed, / And I loved her that she did pity them.
The two halves of the line share the same construction: "she loved me for the dangers" and "I loved her for the pity she felt". The mirroring presents love as an exchange, in which each loves in the other what the other gives.
Act I: Venice, the Night Accusation and the Senate's Judgment, Othello