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