gap> CriticalCells(W);
[ [ 3, 1 ], [ 3, 3148 ], [ 2, 6746 ], [ 2, 20510 ], [ 2, 33060 ], 
  [ 2, 50919 ], [ 1, 29368 ], [ 1, 50822 ], [ 0, 21131 ] ]
gap> CriticalBoundaryCells(W,3,1);
[  ]
gap> CriticalBoundaryCells(W,3,3148);
[ -50919, 50919 ]
