Lateral ends of each wrapping portion are formed into {HEAD ~ a Z shape} to produce {TAIL ~ the Z lock system} 
to produce
Lateral ends of each wrapping portion are formed into { HEAD ~ a Z shape } to produce { TAIL ~ the Z lock system }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL