One end of the tube 45 is in communication with one end of the tube 46, the other end of the tube 46 is in communication with one end of the tube 48, and the other end of the tube 48 is in communication with {HEAD ~ one end} of {TAIL ~ the tube} 50 
of
One end of the tube 45 is in communication with one end of the tube 46 , the other end of the tube 46 is in communication with one end of the tube 48 , and the other end of the tube 48 is in communication with { HEAD ~ one end } of { TAIL ~ the tube } 50
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH