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