{HEAD ~ A rotor} 1 wherein the plurality of {TAIL ~ rings} comprise at least three rings 
{ HEAD ~ A rotor } 1 wherein the plurality of { TAIL ~ rings } comprise at least three rings
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH