{HEAD ~ The faces} of {TAIL ~ the apparatus} can be so shaped that the cross section of the mass being compressed is urged toward a shape other than that of a regular polygon 
of
{ HEAD ~ The faces } of { TAIL ~ the apparatus } can be so shaped that the cross section of the mass being compressed is urged toward a shape other than that of a regular polygon
HEAD HEAD HEAD HEAD HEAD HEAD 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 OTH OTH OTH OTH OTH OTH