public void fillUnobstructedArea(Graphics g, int pixelsize)
    {
        g.setColor(Color.green);
        for (int i = 0; i < gui.getWidth(); i += pixelsize)
            for (int j = 0; j < gui.getHeight(); j += pixelsize)
                if (!AngleElimination.isObstructed(new Vertex(i+pixelsize/2, j+pixelsize/2)))
                    g.fillRect(i, j, pixelsize, pixelsize);
    }