public static void main(String[] args) throws FileNotFoundException  {

        final String FILE_NAME = "data/maze21.txt"; //PUT THE FILE PATH HERE!!
        boolean[][] maze = testreadmaze(FILE_NAME);


        mazepublic = maze;


        JFrame f = new JFrame("Maze");
        f.setSize(len*20+16, len*20+39);
        f.add(new Exercise4());
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);


    }