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