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