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