{HEAD ~ A laser beam} 16 is focused through the opening 13 by a lens 14 and on to {TAIL ~ a panel} of substrate material 18 positioned underneath the opening 13 
{ HEAD ~ A laser beam } 16 is focused through the opening 13 by a lens 14 and on to { TAIL ~ a panel } of substrate material 18 positioned underneath the opening 13
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH