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