{TAIL ~ Each trough shaped reflector} has an associated flat reflecting mirror for directing its beam of illuminating light toward {HEAD ~ the document} 
{ TAIL ~ Each trough shaped reflector } has an associated flat reflecting mirror for directing its beam of illuminating light toward { HEAD ~ the document }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD