Well, let's suppose that this is the partial pressure of carbon dioxide inside the exercising tissue. And so we draw a straight line going upward. Now in this particular case, this line basically did not take into consideration the halding effect. And according to this line, we can only fit this amount of CO2 inside our blood. But if we do take the held in effect into consideration, because we do decrease the oxygen content in our blood next to the exercising tissue, that shifts the curve this way to the left. And so the new Y coordinate is this value here.