{HEAD ~ The cable holder} has two side walls and {TAIL ~ a bottom wall}, with grooves at the tops of the side walls 
has
{ HEAD ~ The cable holder } has two side walls and { TAIL ~ a bottom wall } , with grooves at the tops of the side walls
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH