{HEAD ~ The angle} between two adjacent light focusing means 16, 16 is represented by {TAIL ~ A} 
is represented by
{ HEAD ~ The angle } between two adjacent light focusing means 16 , 16 is represented by { TAIL ~ A }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL