private void drawVisitedEdge(Graphics g, Edge e) {
        int x1 = e.getStart().getX();
        int y1 = e.getStart().getY();
        int x2 = e.getEnd().getX();
        int y2 = e.getEnd().getY();
        g.setColor(Color.BLACK);

        for (int i = -1; i <= 1; i++) {
            for (int j = -1; j <= 1; j++) {
                g.drawLine(x1 + i, y1 + j, x2 + i, y2 + j);
            }
        }
    }