Matrix
**********************



.. code-block:: c++
   :name: a_sample_matrix
   :caption: A 5x7 matrix

        j---> > >
          0   1   2   3   4   5   6
        +---+---+---+---+---+---+---+
   i  0 |   |   |   |   |   |   |   |
   |    +---+---+---+---+---+---+---+
   v  1 |   |   | x |   |   |   |   |
   v    +---+---+---+---+---+---+---+
   v  2 |   |   | x |   |   | x |   |
        +---+---+---+---+---+---+---+
      3 |   |   | x |   |   | x |   |
        +---+---+---+---+---+---+---+
      4 |   |   | x |   |   | x |   |
        +---+---+---+---+---+---+---+


.. toctree::
   :maxdepth: 2

   questions