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