public bool VerifyClockwiseArcResident()
        {
            const int    radius     = 6;
            const double startAngle = Math.PI;
            const double endAngle   = 0;

            var centre = new Point3d(0, 0, 0);

            var arc = new Arc(centre, radius, startAngle, endAngle);

            return(arc.Clockwise());
        }