Power generator 26 and second power generator 28 may provide {HEAD ~ equal power} or may provide {TAIL ~ different power amounts}  
Power generator 26 and second power generator 28 may provide { HEAD ~ equal power } or may provide { TAIL ~ different power amounts }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH