These programs and sample data files generate the EXACT stiffness matrix of
the elements indicated. The subroutines were generated using the Maple
Computer Algebra software system.

The formulations are for straight-sided element, so the data reads only the
corner coordinates, with the intermediate and internal nodes computed
automatically.

The element node numbering is the same as that indicated in Appendix B of the
text, "Programming the finite element method" by I.M. Smith and
D.V. Griffiths, 4th ed., Wiley, 2004