{HEAD ~ One way valves} in the bottom of the dipper allow {TAIL ~ water} to pass into the dipper 
allow
{ HEAD ~ One way valves } in the bottom of the dipper allow { TAIL ~ water } to pass into the dipper
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH