{TAIL ~ The invention} relates to {HEAD ~ structural members} which can be interlocked in end to end fashion to assemble a double wall 
{ TAIL ~ The invention } relates to { HEAD ~ structural members } which can be interlocked in end to end fashion to assemble a double wall
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH