Exercise 13
===========

.. admonition:: Start your assignment

    You can start working on your copy of Exercise 13 by `accepting the GitHub Classroom assignment <https://classroom.github.com/a/W1Kgvcq4>`__.

    **Exercise 13 is due by midnight on 11.12**.

.. tip:: 

    You can also take a look at the open course copy of `Exercise 13 in the course GitHub repository <https://github.com/IntroQG-2017/Exercise-13>`__ (does not require logging in).
    You should not try to make changes to this copy of the exercise, but rather only to the copy available via GitHub Classroom.