// The client code works with an instance of a concrete creator, albeit
// through its base interface. As long as the client keeps working with
// the creator via the base interface, you can pass it any creator's
// subclass.
public void ClientCodeButton(GUIFactory creator)
{
// ...
Console.WriteLine("Client: I'm not aware of the creator's class," +
"but it still works.\n" + creator.FactoryMethodButton());
// ...
}