Total Product and Marginal Product Curves

These are the general shapes behind the lumberjack numbers. Total product (TP) rises slowly at first, then quickly while the extra workers make the fixed capital more productive, then more and more slowly as the capital is stretched thin. Marginal product (MP) is the slope of the total product curve, so it rises while TP is bending upward, peaks where TP is steepest, and then falls as diminishing marginal product sets in.

The sliders move the point where TP is steepest, which is where MP peaks, and change how sharply the switch from increasing to diminishing returns happens.