public void drawGrid(Graphics2D g2) {
        if (backgroundGrid == null) {
            backgroundGrid = generateGrid(5);
        }
        g2.setPaint(strongColor);
        g2.draw(backgroundGrid);

        if (foregroundGrid == null) {
            foregroundGrid = generateGrid(1);
        }
        g2.setPaint(weakColor);
        g2.draw(foregroundGrid);
    }