Such a process is distinguished in that the surface experiencing the air pressure is convex and {HEAD ~ the normals} to the surface converge on {TAIL ~ the rounded shaping vertex} of the shaper 
converge on
Such a process is distinguished in that the surface experiencing the air pressure is convex and { HEAD ~ the normals } to the surface converge on { TAIL ~ the rounded shaping vertex } of the shaper
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH