Hfsow plants the grass objects created by sawrs across a heightfield
surface.  Both hfsow and sawrs use a recursive bounding scheme -- hfsow for
the plant objects, which I considered point objects; sawrs for cylinders, which
I sorted by using one of the points in each cylinder to determine the nearest
neighbors.

        ---Larry Coffin
                lcoffin@clciris.chem.umr.edu


PS.  There's an example of the output on weedeater.math.yale.edu in the incoming
directory called sea_dunes.jpg