return [ [ [ 2, 3, 4, 5 ], [ 1, 5, 6, 7 ], [ 1, 7, 8, 4 ], [ 1, 3, 8, 9 ], 
      [ 1, 9, 10, 2 ], [ 2, 10, 11, 7 ], [ 2, 6, 11, 3 ], [ 3, 11, 9, 4 ], 
      [ 4, 8, 10, 5 ], [ 5, 9, 11, 6 ], [ 6, 10, 8, 7 ] ] ];