Який структурний патерн використано

  class Program

    {

        static void Main(string[] args)

        {

            var spiralBinding = new SpiralBinding();

            var fantasyBook = new FantasyBook("The Name of the Wind", "Patrick Rothfuss", spiralBinding);

            var sciFiBook = new ScienceFictionBook("Dune", "Frank Herbert", spiralBinding);

        }

    }

    interface IBinding

    {

        string Name { get; }

    }

    class Binding : IBinding

    {

        public string Name

        {

            get

            {

                return this.GetType().Name;

            }

        }

    }

    class PerfectBinding : Binding { }

    class SpiralBinding : Binding { }

    class SaddleStitchBinding : Binding { }

    interface IBook

    {

        string Author { get; set; }

        Binding Binding { get; set; }

        string Title { get; set; }

    }

    class Book : IBook

    {

        public string Author { get; set; }

        public Binding Binding { get; set; }

        public string Title { get; set; }

        public Book(string title, string author, Binding binding)

        {

            Author = author;

            Binding = binding;

            Title = title;

            Console.WriteLine($"Created {this.GetType().Name} of \"{title}\" by {author} using {binding.Name}.");

        }

    }

    class MysteryBook : Book

    {

        public MysteryBook(string title, string author, Binding binding) : base(title, author, binding) { }

    }

    class FantasyBook : Book

    {

        public FantasyBook(string title, string author, Binding binding) : base(title, author, binding) { }

    }

    class ScienceFictionBook : Book

    {

        public ScienceFictionBook(string title, string author, Binding binding) : base(title, author, binding) { }

    }