 of the triangles should
      be listed in counterclockwise order, as viewed from outside the surface.
      A normal vector for the triangle may also be listed.
    </p>

    <p>
      A <b>TRI_SURFACE</b> or triangulated mesh surface, is described by a
      pair of arrays:
      <ul>
        <li>
          a <b>node coordinate</b> array containing the coordinates of nodes;
        </li>
        <li>
          a <b>triangle node</b> array containing triples of the indices
          of the nodes used to f