If we add one more oxygen, we get this. And finally, if this one is filled, we get the r state. So the major difference between the concerted model and the sequential model is in the concerted model, we only have either the t state or the r state. But in this particular case, we have the T state, we have the r state, and we also have these three intermediate, intermediate one, intermediate two, and intermediate three. So in the sequential model, the binding of the oxygen stimulates a conformational change in that polypeptide, and that in turn, induces a conformational change in this nearby and this nearby polypeptide chain. And that tells us that because the conformation changes, that will increase the affinity of that heme group for the oxygen molecule.