An example of two forms with a synchronized cursor

MapRunnerDisplay.cs

using System;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;

class MapRunnerDisplay : Form
{
    [STAThread]
    private static void Main()
    {
        Application.Run(new MapRunnerDisplay());
    }

    private Point movingPoint = Point.Empty;

    private MapRunnerDisplay()
    {
        Load += MapRunnerDisplay_Load;
        MouseMove += MapRunnerDisplay_MouseMove;
        Paint += MapRunnerDisplay_Paint;
    }

    private void MapRunnerDisplay_Load(object sender, EventArgs e)
    {
        if (Application.OpenForms.Count != 1) return;
        var another = new MapRunnerDisplay
        {
            StartPosition = FormStartPosition.Manual, 
            Location = new Point(Location.X + Width, Location.Y + Height)
        };
        another.Show();
    }

    private void MapRunnerDisplay_MouseMove(object sender, MouseEventArgs e)
    {
        foreach (var another in Application.OpenForms.OfType<MapRunnerDisplay>())
        {
            another.UpdatePosition(e.Location);
        }
    }

    private void UpdatePosition(Point point)
    {
        movingPoint = point;
        Invalidate();
    }

    private void MapRunnerDisplay_Paint(object sender, PaintEventArgs e)
    {
        e.Graphics.Clear(Color.White);
        e.Graphics.DrawEllipse(new Pen(Color.Red), movingPoint.X - 2, movingPoint.Y - 2, 4, 4);
    }
}