This example gives a short introduction of the CMISS environment and
of how to construct a simple 2D mesh. You will use the 2D graphics
window to create a simple finite element model. Nodes are located by
clicking in the window and particular care must be taken when linking
the nodes into elements.  The order in which the nodes are selected is
critical, but not initially intuitive!  Incorrectly specifying this
order will result in highly distorted geometries.  In practice, mesh
creation would be automated (or specified through files), but is
manually done here to demonstrate the process.