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