Each one of the drive gears constantly meshes with {TAIL ~ its counterpart member} of {HEAD ~ the driven gears} 
Each one of the drive gears constantly meshes with { TAIL ~ its counterpart member } of { HEAD ~ the driven gears }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD