{HEAD ~ a first rotor} which is connected to the output shaft of {TAIL ~ the internal combustion engine} 
{ HEAD ~ a first rotor } which is connected to the output shaft of { TAIL ~ the internal combustion engine }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL