Each of {HEAD ~ the partitions} has hooks and notches to help hold {TAIL ~ the assembly} together 
Each of { HEAD ~ the partitions } has hooks and notches to help hold { TAIL ~ the assembly } together
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH