return [ [ 2, 3, 4, 5 ], [ 1, 5, 6, 7 ], [ 1, 7, 8, 4 ], [ 1, 3, 9, 10 ], 
  [ 1, 10, 11, 2 ], [ 2, 11, 12, 13 ], [ 2, 13, 14, 3 ], [ 3, 14, 15, 9 ], 
  [ 4, 8, 16, 17 ], [ 4, 17, 18, 5 ], [ 5, 18, 19, 6 ], [ 6, 19, 20, 21 ], 
  [ 6, 21, 22, 7 ], [ 7, 22, 23, 8 ], [ 8, 23, 24, 16 ], [ 9, 15, 25, 26 ], 
  [ 9, 26, 27, 10 ], [ 10, 27, 28, 11 ], [ 11, 28, 29, 12 ], 
  [ 12, 29, 30, 31 ], [ 12, 31, 22, 13 ], [ 13, 21, 23, 14 ], 
  [ 14, 22, 31, 15 ], [ 15, 31, 30, 25 ], [ 16, 24, 30, 32 ], 
  [ 16, 32, 27, 17 ], [ 17, 26, 28, 18 ], [ 18, 27, 32, 19 ], 
  [ 19, 32, 30, 20 ], [ 20, 29, 25, 24 ], [ 20, 24, 23, 21 ], 
  [ 25, 29, 28, 26 ] ];
