{HEAD ~ The walls} of {TAIL ~ the light trap structure} 42 have reflective and non reflective interior surfaces which are indicated at 92, 94, respectively 
{ HEAD ~ The walls } of { TAIL ~ the light trap structure } 42 have reflective and non reflective interior surfaces which are indicated at 92 , 94 , respectively
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH