private IDetail CreateDetail()
        {
            IDetail bolt  = new Bolt();
            IDetail nail  = new Nail();
            IDetail screw = new Screw();
            IDetail wheel = new Wheel();

            IDetail[] details = new IDetail[] { bolt, nail, screw, wheel };

            int index = rnd.Next(4);

            return(checkerContainer.CreateDetail(details[index]));
        }