This figure shows a graph that has Time along the horizontal axis and Functional Demand along the vertical axis.

The graph starts at 8:00 and a functional demand of zero. By 10:00, the functional demand is at the peak workload, and by 12:00 the functional demand has dropped to a little above the average workload.

A little before 14:00, the functional demand is at the peak workload again, and by 16:00 the functional demand has dropped back down to zero.