StaticPoint

 class Point3D
    {
        private double x;
        private double y;
        private double z;
        private static readonly Point3D startingPoint;

        static Point3D()
        {
            startingPoint = new Point3D(0, 0, 0);
        }


        public double X
        {
            get { return this.x; }
            set { this.x = value; }
        }
        public double Y
        {
            get { return y; }
            set { y = value; }
        }
        public double Z
        {
            get { return z; }
            set { z = value; }
        }

        public Point3D StartingPoint
        {
            get { return startingPoint; }
        }

        public Point3D(double a=0, double b=0, double c=0)
        {
            this.X = a;
            this.Y = b;
            this.Z = c;
        }
}