{HEAD ~ The forward edge 136 proceeds} downwardly to {TAIL ~ a point} 150, and a sharpened bottom edge 152 inclines upwardly from the point 150 to the rear edge 138 
{ HEAD ~ The forward edge 136 proceeds } downwardly to { TAIL ~ a point } 150 , and a sharpened bottom edge 152 inclines upwardly from the point 150 to the rear edge 138
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH