{TAIL ~ The reflectors} comprise ruled surfaces and are arranged to converge from {HEAD ~ entrance} to exit apertures 
{ TAIL ~ The reflectors } comprise ruled surfaces and are arranged to converge from { HEAD ~ entrance } to exit apertures
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH