{HEAD ~ The non extension end edge} of each panel is connected to the opposing panel by {TAIL ~ a flat connecting wall} 
is connected by
{ HEAD ~ The non extension end edge } of each panel is connected to the opposing panel by { TAIL ~ a flat connecting wall }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL