open Dm5;;

assert (rotation
  [|
    [| 1; 5; 9 |];
    [| 2; 6; 10 |];
    [| 3; 7; 11 |];
    [| 4; 8; 12 |]
  |]
  =
  [|
    [| 9; 10; 11; 12 |];
    [| 5; 6; 7; 8 |];
    [| 1; 2; 3; 4 |]
  |]
);;
assert (rotation [||] = [||]);;
assert (rotation [|[||]; [||]|] = [||]);;

assert (plsci [||] = (0,0));;
assert (plsci [|1|] = (0,1));;
assert (plsci [|1; 1|] = (0,2));;

assert (dominant "aaetisanutesn'gqphteiuatnstbm(mab" = 'a');;