But then that just becomes somewhat crazy because you're literally thinking of all possible things. Normally when people talk about a universal set, they're talking about a universe of things that they care about. So the set of all people or the set of all real numbers or the set of all countries, whatever the discussion is being focused on. But we'll talk about an abstract terms right now. And let's say you have a subset of that universal set. So let's say you have a subset of that universal set, set A. And so set A literally contains everything, everything that I have just shaded in.