A first fixed reflecting surface of a parabolic group reflecting surface can include {HEAD ~ a focus} on {TAIL ~ the second focus} of the first reflecting surface, and at least two second reflecting surface elements 
A first fixed reflecting surface of a parabolic group reflecting surface can include { HEAD ~ a focus } on { TAIL ~ the second focus } of the first reflecting surface , and at least two second reflecting surface elements
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH