The “first leg” corresponds to {TAIL ~ one leg} of {HEAD ~ the biped walking robot} and the “second leg” corresponds to the other leg thereof 
The “ first leg ” corresponds to { TAIL ~ one leg } of { HEAD ~ the biped walking robot } and the “ second leg ” corresponds to the other leg thereof
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH