This applet looks at constructing a surface from its level sets (contours).

• It opens with a control window and three graphics windows.
• Domain window gives the countour map of the function.
• The Level Curves window shows the graph of the function being cut by a plane at height z0.  The value of z0 can be found and modified in the control window.   The level curve at this height is in orange.
• The graph window shows the graph and the level curves on the graph.  The level curve generated by the cutting plane in the previous window also shows up.
• Notice that is the graph window is viewed using the view menu iten "Up the Z axis" we will reproduce the domain window.