Floor 44 is formed with steps 46 at an interior edge of opening 45 on which a plate 48 rests, {TAIL ~ the opening} being covered by {HEAD ~ the plate} 
Floor 44 is formed with steps 46 at an interior edge of opening 45 on which a plate 48 rests , { TAIL ~ the opening } being covered by { HEAD ~ the plate }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD