{TAIL ~ A high reflector} is affixed to the optics plate and configured to receive {HEAD ~ the fourth reflected beam} 
{ TAIL ~ A high reflector } is affixed to the optics plate and configured to receive { HEAD ~ the fourth reflected beam }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD