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 {HEAD ~ fact} the opposite surface of {TAIL ~ 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 { HEAD ~ fact } the opposite surface of { TAIL ~ 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 HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH