How does the cause become the effect and the effect becomes the cause in a story?

There are a couple ways you can do it. You could have time travel in your story where something from the past goes back in time to change something else, and in turn ends up causing the thing they went to stop from happening. (example - I go back to stop a murder and end up killing the person myself) Or you can have some sort of feedback loop, where the cause and effect feed into one another. (example - I buy apples because you ate them, and because I bought apples you eat them, and so I buy some, and so on and so forth)