The first cusp includes 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 {TAIL ~ the opposite surface} of {HEAD ~ reflector} 73 
The first cusp includes 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 { TAIL ~ the opposite surface } of { HEAD ~ reflector } 73
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 OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH