The outer peripheral side honeycomb unit has an outer peripheral cell wall forming {HEAD ~ the outer peripheral surface} of {TAIL ~ the outer peripheral side honeycomb unit} 
of
The outer peripheral side honeycomb unit has an outer peripheral cell wall forming { HEAD ~ the outer peripheral surface } of { TAIL ~ the outer peripheral side honeycomb unit }
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 TAIL TAIL TAIL