    Conceptual Model of the Game
    -----------------------------------------------------------------------------

    =============================================================================
    Purpose:

    The project implements a (silly) game. N players meet at a table and roll a
    die. Every player rolls the die once per round. They add up their scores.
    A player can skip his turn or declare that he is done. A player is
    eliminated if/when his score surpasses 21.

    We allow people to write players and to add them to our game. Some of the
    players may be interactive. (Ignore remote display concerns)

    End of game:
     The game is over when all players are eliminated or done.

    Scoring:
     The winners are those players with the maximum score.

    The conceptual model:

     +--------+ 1                     * +--------+
     | Server | <---------------------> | Player |
     +--------+                         +--------+
        |    ^1                           ^ 1
        |    |        * +------+ *        |
        |    +--------> | Turn | <--------+
        |               +------+
        |
        \/1
     +--------+
     | Die    |
     +--------+