namespace DesignPattern.Structural.Facade{    public class Facade    {        readonly ProductA _productA = new ProductA();        readonly ProductB _productB = new ProductB();        public void Show()        {            _productA.ShowA();            _productB.ShowB();        }    }    public class ProductA    {        public void ShowA() { }    }    public class ProductB    {        public void ShowB() { }    }}