Draw multiple lines on mouse click but without overlapping

Question

this code is working for drawing multiple lines by mouse clicks. But the lines are overlapping or intersecting even if one line is already created.

Can anyone help me how can i draw multiple lines [the working code for drawing multiple lines are given] without overlapping each other inestead it would find another round way to avoid conflicts to other lines.

    public partial class Form1 : Form
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }

    private Point _setPointA, _setPointB;
    private static List<Point> PointList = new List<Point>();
    private Dictionary<Point, Point> PointDictionary = new Dictionary<Point, Point>();

    public Form1()
    {
        PointDictionary.Add(new Point { X = 10, Y = 10 }, new Point { X = 85, Y = 85 });

    }
    protected override void OnMouseClick(MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            if (!PointList.Any())
            {
                _setPointA = e.Location;
                PointList.Add(_setPointA);
            }
            else
            {
                _setPointB = e.Location;
                PointList.Add(_setPointB);

                //check if not intersects

                if (_setPointA.X <= _setPointB.X)
                {
                    PointDictionary.Add(_setPointA, _setPointB);
                }
                else
                {
                    PointDictionary.Add(_setPointB, _setPointA);
                }
                Refresh();
            }
        }
        base.OnMouseClick(e);
    }
    protected override void OnPaint(PaintEventArgs e)
    {
        foreach (var v in PointDictionary)
        {
            e.Graphics.DrawLine(SystemPens.ControlDarkDark, v.Key, v.Value);
        }

        base.OnPaint(e);
        PointList.Clear();
    }
}