Notes about the Pointwise grids:
   "CRM-HL_Unstr-Tet_Level-X_PW"
   "CRM-HL_Unstr-Prism-Tet_Level-X_PW"
   "CRM-HL_Unstr-Hex-Prism-Pyr-Tet_Level-X_PW"

   with X = A, B, C, D, E, and F in reference to the different refinement levels.

The various grids are very closely related, as described below.

Tet Grids
  - Triangular surface mesh is created on version V1a of the CRM-HL geometry.
  - Each vertex on the surface mesh is advanced normal to the surface based on specified wall spacing.
  - Once each of the surface mesh vertices have been advanced, you have one layer of anisotropic
    tetrahedra containing a stack of three right-angle tets on each surface triangle.
  - The vertices of the triangles on top of this anisotropic layer can then be advanced in the same
    manner and this process continues until the final right-angle tets in the stack of layers have
    reached an isotropic state, they have collided with a grid boundary or another front of the grid, or
    the defined quality criteria have been violated.
  - The remainder of the volume is filled in with isotropic tets.


Prism-Tet Grids
  - Triangular surface mesh is created on version V1a of the CRM-HL geometry.
  - Each vertex on the surface mesh is advanced normal to the surface based on specified wall spacing.
  - Once each of the surface mesh vertices have been advanced, you have one layer of anisotropic
    tetrahedra containing a stack of three right-angle tets on each surface triangle.
  - This stack of three right-angle tets are evaluated to determine if the prism that could be
    created from them would contain a negative component volume. In other words, Pointwise cannot
    predict how flow solver might decompose a prism so each of the 12 different ways a prism
    could be decomposed into 3 tets are reviewed and evaluated.  If any of those decompositions
    results in one of the component tet volumes being negative, the three anisotropic tets are not
    combined into a prism.
  - The vertices of the triangles on top of this layer (whether it's the top of a right-angle tet or
    a prism) can then be advanced in the same manner to create a new layer.  This new layer is evaluated to
    determine if a valid prism would be created by the same process used in the previous step.
  - The stack of layers continue to grow until they have reached an isotropic state, they have collided
    with a grid boundary or another front of the grid, or the defined quality criteria have been violated.
  - The remainder of the volume is filled in with isotropic tets.

Comparing the two techniques, it's not just a brute force combination of cells. There is the
possibility that there could be a small pocket of tets in a few spots amongst the prisms if
creating prisms would create negative volume cells.  That being said, there does not appear
to be very much of this in most grids, and they should be almost identical.  Nonetheless, there
is still the possibility of a small amount of tets left uncombined.


Hex-Prism-Pyr-Tet Grids

These grids are created in a similar manner, except that each layer of anisotropic tets is grown off of
a surface mesh containing both triangular and quadrilateral (represented with two triangles) cells.
At each layer, Pointwise evaluates if every pair of prisms could form a valid unstructured hex of acceptable
quality. If they do, a new hex is formed. On the other hand, if they don't, the prisms are not combined and
this could lead to having small pockets of prisms in between anisotropic layers; this does not happen often.
A the top of each hex stack, a cap is created from a pyramid surrounded.