interface Directions { //global Constants
  static final int north = 0, east = 1, south = 2, west = 3;
}

// ------------------------------------------------------------

class MapSite {
  void Enter() {/* ... */};
}

// ------------------------------------------------------------

class Room extends MapSite {
 
  private MapSite[] sides = new MapSite[4];
  private int roomNo;
  
  Room(int roomNo) {
    this.roomNo = roomNo;
  }
  
  MapSite GetSide(int direction) {/* ... for now: */ return null;};
  
  void SetSide(int direction, MapSite ms) {
    sides[direction] = ms;
  };
}

// ------------------------------------------------------------

class DoorWall extends MapSite {
 
  private Room r1;
  private Room r2;
  private boolean isOpen;
  
  DoorWall(Room r1, Room r2) {
    this.r1 = r1;
    this.r2 = r2;
    this.isOpen = false;
  };
  
  Room OtherSideFrom(Room r) {return null; /* for now */};
}

// ------------------------------------------------------------

class Maze {
  void AddRoom(Room r) {};
  Room RoomNo(int r) {return null;};
}

// ------------------------------------------------------------

class Wall extends MapSite {
}



class MazeGame implements /* uses */ Directions {
  public static void main(String[] argv) {
    CreateMaze();
  }
  
  static Maze CreateMaze() {
    Maze aMaze = new Maze();
    Room r1 = new Room(1);
    Room r2 = new Room(2);
    DoorWall d  = new DoorWall(r1, r2);

    aMaze.AddRoom(r1);
    aMaze.AddRoom(r2);

    r1.SetSide(north, new Wall());
    r1.SetSide(east,  d);
    r1.SetSide(south, new Wall());
    r1.SetSide(west,  new Wall());

    r2.SetSide(north, new Wall());
    r2.SetSide(east,  new Wall());
    r2.SetSide(south, new Wall());
    r2.SetSide(west,  d);

    return aMaze;
  }
}