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