This is the "Netkit" example from Chapter 20 of "The Book of GENESIS",
illustrating how some of the advanced XODUS draw widget objects and commands
may be used to construct a simple network builder.

Use the mouse to drag prototype cells from the library window into the work
window below it.  To bring up the parameter edit window in the lower left
corner, double click on the cell to edit in the work window.  Click and drag
one cell to another in order to establish a connection, and drag the cell
into the graph window in order to plot Vm for the cell.

