EDIT: On rereading your question, it seems I associated it with the wrong section of the article, matching to a question I asked and answered for myself when reading it.
The last two steps in the simplification get combined into one step, and then the next pass combines that step with the previous step, and so on until all the steps are combined and the last pass does not combine any steps so you know that you are done.
EDIT: On rereading your question, it seems I associated it with the wrong section of the article, matching to a question I asked and answered for myself when reading it.
The last two steps in the simplification get combined into one step, and then the next pass combines that step with the previous step, and so on until all the steps are combined and the last pass does not combine any steps so you know that you are done.