Building a wire frame model

Mike May
This illustrates the first example in section 6.2 Wire Frames, Partial Derivatives, and Tangent Planes in Business Calculus with Excel
We have been given the function Revenue(QG, QW) =10QG - QG^2/50 + 20QW -QW^2/40 As the revenue function for a business that makes Gizmos and Widgets. We want to see how the surfqace can be modeled by a wire frame constructed by knowing functions in one variabel