Someone is saying how close they want f of x to be to l. And the burden is then to find a delta where as long as x is within delta of c, then f of x will be within epsilon of the limit. So that is doing it. It's saying, look, if we were constraining x in such a way that if x is in that range to c, then f of x will be as close as you want. So let's make this a little bit clearer by diagramming right over here. You show up and you say, well, I want f of x to be within epsilon of our limit. So this right over here, this point right over here is our limit plus epsilon. And this right over here might be our limit minus.