{TAIL ~ Each pair} of {HEAD ~ ground wheels} 16 is mounted to the rear end of an arm 18 that is positioned between the legs of, and pivotally attached to, a main channel like arm 20 
{ TAIL ~ Each pair } of { HEAD ~ ground wheels } 16 is mounted to the rear end of an arm 18 that is positioned between the legs of , and pivotally attached to , a main channel like arm 20
TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH