{HEAD ~ The housing} 20 is generally rectangular in {TAIL ~ shape}, but may have any suitable shape 
is generally rectangular in
{ HEAD ~ The housing } 20 is generally rectangular in { TAIL ~ shape } , but may have any suitable shape
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH