public Point3D Subtract(Point3D p2) { return new Point3D(x - p2.x, y - p2.y, z - p2.z); }
public Point3D(Point3D other) : this(other.x, other.y,other.z) { }
public Point3D Add(Point3D p2) { return new Point3D(x + p2.x, y + p2.y, z + p2.z); }