Scherk's Minimal Surface
Scherk's minimal surface arises from the solution to a differential equation that describes a minimal monge patch (i.e., a patch that maps [u, v] to [u, v, f(u, v)]). The full surface is obtained by putting a large number of the small units pictured above next to each other in a chessboard pattern, as shown below. The plots below were made by plotting the implicit definition of the surface.
The definition of Scherk's surface as a monge patch is