I remember when my son was about seven years old, he made me very angry. I came home from work and he was out somewhere playing, and hadn’t done any of the chores that I told him to do. I couldn’t find a sheet of paper, so I grabbed an empty soda can and a marker, and I wrote on it the entire list of things I was ordering him to do, and tossed it into his room. When he came home and saw the list, he immediately followed my orders and it was never an issue after that. And because of what my firm instructions were written on, he referred to it as the “tin” commandments.