Symploce

Symploce is the combination of anaphora and epistrophe: the same words open each successive clause and the same words close it, so the only element that changes is the one in the middle.

They say the delay was unavoidable. They say the cost was unavoidable. They say the silence was unavoidable.

They say opens each clause; was unavoidable closes each one. Everything the reader is being asked to weigh — delay, cost, silence — sits in the gap between the two fixed brackets, and the frame makes the list impossible to miss.

That is the whole mechanism: by holding both ends still, symploce turns a sentence into a slot, and the reader compares what goes into it. It is anaphora and epistrophe at the same time, and it is the most controlled member of the repetition family.

Because the pattern is so visible, it reads as constructed. That makes it excellent in argument, in a closing paragraph, and in the mouth of a character who has thought about what they are going to say — and wrong in the mouth of one who is improvising.

Three instances is the practical limit. The frame is doing a lot of work, and a fourth repetition tips it from emphatic into incantatory.

The related figure that inverts rather than repeats is chiasmus.