This illustration shows a graph that has Time along the horizontal axis and Functional Demand along the vertical axis. The graph start at 8:00 and a functional demand of zero.

By 10:00, the functional demand is at the peak workload; by 12:00, the functional demand has dropped a little above the average workload. A little before 14:00, the functional demand is at the peak workload again; by 16:00, the functional demand has dropped back to zero.

End of image description.