Some interesting examples on how the writing and the erasing are almost one.
Putting Water on a Carpet by a Jewish or Non-Jewish Person;
What are the circumstances needed to consider one's actions "מדידה של מצוה" (measuring for a mitzvah).
הכנה לחול (Preparations for a Weekday): Is There a Limit to the Amount of Exertion Used When Doing the Action?;