Thanks for linking the pic of a 'Lanchester/Prandtl surface of discontinuity in reverse.'
I find this illustration particularly comprehnsive.
You find Wake boards in the upper left. I've never seen an example of the High momentum mud flap. The stepped box is especially helpful with the tail lights.
I think the egg-crate construction in the patent drawing could be reduced to triangles, but anything more would reduce rigidity, so why not?