>>> mat_tout_no(5)
array([[0, 1, 1, 1, 1],
       [0, 0, 1, 1, 1],
       [0, 0, 0, 1, 1],
       [0, 0, 0, 0, 1],
       [0, 0, 0, 0, 0]])

>>> mat_serveur_o(5)
array([[0, 1, 1, 1, 1],
       [1, 0, 0, 0, 0],
       [1, 0, 0, 0, 0],
       [1, 0, 0, 0, 0],
       [1, 0, 0, 0, 0]])