code: @Override
      protected void prepareGUI(Container container)
      {
          sudokuView = new SudokuView();
          container.add(createControls(), BorderLayout.NORTH);
          container.add(sudokuView, BorderLayout.CENTER);
          statusBar = new StatusBar();
          container.add(statusBar, BorderLayout.SOUTH);
          sudokuView.setPuzzle(EASY_PUZZLE);
      }
docs: Initialise and layout the GUI.
  @param container The Swing component that will contain the GUI controls.