{TAIL ~ a pair} of liquid containers at substantially the same level including a water container and {HEAD ~ a detergent container} 
{ TAIL ~ a pair } of liquid containers at substantially the same level including a water container and { HEAD ~ a detergent container }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD