{HEAD ~ an elongated hopper door} extending across {TAIL ~ the full width} of the box along the bottom of the hopper to form a part of the bottom thereof 
extending across
{ HEAD ~ an elongated hopper door } extending across { TAIL ~ the full width } of the box along the bottom of the hopper to form a part of the bottom thereof
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH