Fixed Point Combinator in C#

Program.cs

using System;

namespace ConsoleApp1
{
    class Program
    {
        delegate T Out<T>(T x);
        delegate Out<T> RecOut<T>(RecOut<T> x);
        class YClass<T>
        {
            public static Out<T> Y (Out<Out<T>> g) {
                RecOut<T> callIt = x => x(x);
                return callIt(x => y => g(x(x))(y));
            }
        }
        static void Main(string[] args)
        {
            Console.WriteLine(YClass<int>.Y(f => x => x == 0 ? 1 : x * f(x - 1))(6));
            Console.ReadLine();
        }
    }
}

Beautiful