protected void paintComponent(Graphics g) {
        g.setColor(Color.red);
        g.drawLine(0, getHeight() / 2, getWidth(), getHeight() / 2);
        g.setColor(Color.magenta);
        g.drawRect(30, 50, 80, 90);
        g.fillRect(30, 50 + getHeight() / 2, 80, 90);

    }