The plow is positioned so that the lower edge of {HEAD ~ the blade}, which is bolted upon {TAIL ~ the forward face} of the moldboard, rests upon the ground 
The plow is positioned so that the lower edge of { HEAD ~ the blade } , which is bolted upon { TAIL ~ the forward face } of the moldboard , rests upon the ground
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH