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