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 {TAIL ~ fact} {HEAD ~ the opposite surface} of reflector 73 
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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 { TAIL ~ fact } { HEAD ~ the opposite surface } of 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 REL TAIL TAIL TAIL TAIL TAIL HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH