{
    PjApplication app = new PjApplication();
    app.setLayout(null);
    app.setVisible(true);
    int num = (int) (Math.random()*10)+6;
    PjOval[] list = new PjOval[num];
    for (int i = 0; i < list.length; i++){
        PjOval shape = new PjOval();
        shape.setBackground((new Color[] {Color.red, Color.blue, Color.green})[(int)(Math.random()*3)]);
        shape.setLocation((int)(Math.random()*app.getWidth() - shape.getWidth()/2), (int)(Math.random()*app.getHeight() - shape.getHeight()/2));
        app.add(shape);
    }
}