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