Our mutual sense of code manifested in many little games. The most unshakable was called One Day–Two Day. The premise was simply that one of us always had to be vigilant, the designated protector. If Robert took a drug, I needed to be present and conscious. If I was down, he needed to stay up. If one was sick, the other healthy. It was important that we were never self-indulgent on the same day.
— Just Kids (Patti Smith), Loc. 571–4