The tub has sidewalls defining arm rests, end walls defining a foot rest and back rest, and {TAIL ~ a bottom} defining {HEAD ~ a seat} 
The tub has sidewalls defining arm rests , end walls defining a foot rest and back rest , and { TAIL ~ a bottom } defining { HEAD ~ a seat }
OTH OTH OTH OTH OTH OTH 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