public class Doodle
{
    private Pen pen;
    /**
     * A constructor which creates a default canvas
     */
    public Doodle()
    {
        new Pen(280, 220, new Canvas("My canvas", 560, 440));
    }

    /**
     * A method that pauses the program for the given length of
     * time, in milliseconds.
     * This can be used when you want to animate with
     * a delay between drawings.
     *
     * @param howLong How long to pause for, in milliseconds.
     */
    private void pause(long howLong)
    {
        try {
            Thread.sleep(howLong);
        }
        catch(InterruptedException e) {
        }
    }

    /**
     * A method which draws a line between two points
     * @param startX The starting x co-ordinate
     * @param startY The starting y co-ordinate
     * @param endX The ending x co-ordinate
     * @param endY The ending y co-ordinate
     */
    public void betweenTwoPoints(int startX, int startY)
    {
    }

    /**
     * Draw a square
     * @param length The length of the four sides of the square
     */
    public void square(int length)
    {
    }
}