{HEAD ~ Free ends} of roving protrude from borehole openings and are splayed apart into {TAIL ~ individual filaments}  
are splayed apart into
{ HEAD ~ Free ends } of roving protrude from borehole openings and are splayed apart into { TAIL ~ individual filaments }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH