1 　　public class Recursive
 2     {
 3         delegate T SelfApplicable<T>(SelfApplicable<T> self);
 4 
 5         public static void Run()
 6         {
 7             // The Y combinator
 8             SelfApplicable<Func<Func<Func<int, int>, Func<int, int>>, Func<int, int>>> Y =
 9                 y =>
10                     f =>
11                         x => f(y(y)(f))(x);
12             
13             // The fixed point generator
14             Func<Func<Func<int, int>, Func<int, int>>, Func<int, int>> Fix = Y(Y);
15 
16             // The higher order function describing factorial
17             Func<Func<int, int>, Func<int, int>> F =
18                 fac =>
19                     x =>
20                         x == 0 ?
21                             1 :
22                             x * fac(x - 1);
23 
24             // The factorial function itself
25             Func<int, int> factorial = Fix(F);
26 
27             Console.WriteLine(factorial(10));
28 
29         }
30 
31     }

1 new Func<int, int>(i =>
2                 new Func<Func<int, int>, Func<int, int>>(fac => x => x == 0 ? 1 : x * fac(x - 1))(
3                     new SelfApplicable<Func<Func<Func<int, int>, Func<int, int>>, Func<int, int>>>(
4                         y => f => x => f(y(y)(f))(x)
5                     )(
6                         y => f => x => f(y(y)(f))(x)
7                     )(
8                         fac => x => x == 0 ? 1 : x * fac(x - 1))
9                     )(i))(10)