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