The first side and the second side {HEAD ~ each} has an upper portion and {TAIL ~ a lower portion} 
The first side and the second side { HEAD ~ each } has an upper portion and { TAIL ~ a lower portion }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL