twin objects pattern

twins.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Twins
{
    class Program
    {
        static void Main(string[] args)
        {
            var c = new C();
            c.Foo();
            ((B)c).Bar(); 
            c.WhatEver();

            B b = c;
            b.Bar();
            C c2 = b;
            c2.WhatEver();
            Console.WriteLine(Object.ReferenceEquals(c, c2));
            Console.ReadKey();
        }
    }

    public class A 
    {
        public void Foo() {
            Console.WriteLine("A.Foo");
        }
    }

    public class B
    {
        public void Bar() {
            Console.WriteLine("B.Bar");
        }
    }

    public class C : A//,B -imitatin thought CB
    {
        public void WhatEver()
        {
            Console.WriteLine("C.WhatEver");
        }

        private class CB : B
        {
            public readonly C c;
            public CB(C c)
            {
                this.c = c;
            }
        }

        public C()
        {
            b = new CB(this);
        }

        private readonly CB b;

        public static implicit operator B(C obj)
        {
            return obj.b;
        }

        public static implicit operator C(B obj)
        {
            if (obj is CB) return (obj as CB).c;
            throw new ArgumentException();
        }
    }

    
}