A pack containing an article such as a bar of soap consists of {HEAD ~ an inner tubular liner} within {TAIL ~ an outer wrapper} 
within
A pack containing an article such as a bar of soap consists of { HEAD ~ an inner tubular liner } within { TAIL ~ an outer wrapper }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL