Real GDP per hour worked, Y/L pwpf, (T) pwpf2 C pwpf, A B (* ) ( 4 ), Capital per hour worked, K/L Text description of graph Diminishing marginal returns is illustrated in the per-worker production function in the graph above by a movement: O from pwpf 2 to pwpf 1 up along any of the production functions from pwpf 1 to pwpf 3 from pwpf1 to pwpf2