{HEAD ~ The reflection board} can be located adjacent and extend along {TAIL ~ the one flat surface} of the light guide 
extend along
{ HEAD ~ The reflection board } can be located adjacent and extend along { TAIL ~ the one flat surface } of the light guide
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH