{HEAD ~ a planetary gear} that meshes with each of {TAIL ~ the sun gear} and the ring gear, and 
{ HEAD ~ a planetary gear } that meshes with each of { TAIL ~ the sun gear } and the ring gear , and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH