said {HEAD ~ core} formed of {TAIL ~ polypropylene} and said coating formed of polyethylene, 
formed of
said { HEAD ~ core } formed of { TAIL ~ polypropylene } and said coating formed of polyethylene ,
OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH