It can be seen that {HEAD ~ two clips} 18 are locked to {TAIL ~ the exterior and intermediate sheets} 15 and 16, and the clips 18 at their corrugations 22 are locked to the sheets 16 16 and 17 17 
It can be seen that { HEAD ~ two clips } 18 are locked to { TAIL ~ the exterior and intermediate sheets } 15 and 16 , and the clips 18 at their corrugations 22 are locked to the sheets 16 16 and 17 17
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH