public void panel1_Paint_1(object sender, PaintEventArgs e)
        {
            Pen blackPen = new Pen(Brushes.Black);

            for (int y = 0; y <= 6; ++y)
            {
                e.Graphics.DrawLine(blackPen, 0, y * 80, 6 * 80, y * 80);
            }

            for (int x = 0; x <= 6; ++x)
            {
                e.Graphics.DrawLine(blackPen, x * 80, 0, x * 80, 6 * 80);
            }
        }