Elongated {TAIL ~ tub} 16 has {HEAD ~ a pair} of upstanding sidewalls 18, 20 and a pair of upstanding end walls 22, 24 
Elongated { TAIL ~ tub } 16 has { HEAD ~ a pair } of upstanding sidewalls 18 , 20 and a pair of upstanding end walls 22 , 24
OTH 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 OTH OTH