{HEAD ~ The yarn} is fed through {TAIL ~ a hole} in the wall of the tube from a groove on the outer surface 
is fed through
{ HEAD ~ The yarn } is fed through { TAIL ~ a hole } in the wall of the tube from a groove on the outer surface
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH