Underground Sandwiches, a sandwich shop, has the following marginal physical product curve (labeled MPP) for its hourly production.

Note: Marginal values are sometimes plotted between integers (to indicate that they represent changes incurred in moving from one integer to the next), and sometimes they are plotted directly on the integers with which they are associated. For the context of this graph, they are plotted between integers. For example, if the marginal physical product from one unit of labor to two is x, this point is plotted at (1.5, x).