{HEAD ~ a motor} coupled to {TAIL ~ the impeller}, the motor to rotate the impeller to pump a liquid coolant 
coupled to
{ HEAD ~ a motor } coupled to { TAIL ~ the impeller } , the motor to rotate the impeller to pump a liquid coolant
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH