{HEAD ~ The first cusp} includes {TAIL ~ a concave parabolic reflector} 72 above a plane reflector 73, while the latter cusp includes a concave parabolic reflector 74 below a plane reflector 75 which is in fact the opposite surface of reflector 73 
includes
{ HEAD ~ The first cusp } includes { TAIL ~ a concave parabolic reflector } 72 above a plane reflector 73 , while the latter cusp includes a concave parabolic reflector 74 below a plane reflector 75 which is in fact the opposite surface of reflector 73
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL 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 OTH OTH OTH OTH OTH OTH OTH