{TAIL ~ A cw CO2 laser} disposed for transmitting a second beam in {HEAD ~ a second direction} 
{ TAIL ~ A cw CO2 laser } disposed for transmitting a second beam in { HEAD ~ a second direction }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD