This Demonstration shows how the variation of different parameters of the two-period model changes the utility maximizing solution for a consumer deciding what to consume in the first period ( axis) and in the second period ( axis), constrained to a piecewise, two-period budget. The maximizing process is performed with a standard Cobb–Douglas utility function and decides whether the consumer is a saver or a borrower (given by the distance between the blue dashed line and the green dotted line).