There is apparatus for creating a beam of a material being input thereto and for selectively including or not including {HEAD ~ respective ones} of a plurality of {TAIL ~ materials} within the beam 
There is apparatus for creating a beam of a material being input thereto and for selectively including or not including { HEAD ~ respective ones } of a plurality of { TAIL ~ materials } within the beam
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH