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