My solution to David Poeschl's (‏@dpoeschl) twitter code golf challenge

WhatTheFunc

//    Make this C# code compile with minimal additional code (no commenting, etc.): Foo(0)(1)("two")("three")(4)(5)("six")("seven")(8)(9)("ten!");
//        https://twitter.com/dpoeschl/status/275464052216573952
//    How much more code to enforce the argument type pattern (i.e. int, int, string string, int, int, string, string...)?
//        https://twitter.com/dpoeschl/status/275477464183103488
//        https://twitter.com/dpoeschl/status/275478110290444288
//        https://twitter.com/brianfriesen/status/275479513490669568

delegate WhatTheFunc<T2,T3,T4,T1> WhatTheFunc<T1,T2,T3,T4>(T1 _);

void CreateFoo()
{
    WhatTheFunc<int, int, string, string> Foo = null;   // The first function needs to start out null because we have a cycle of functions.
    WhatTheFunc<string, int, int, string> c = _ => Foo; // If it wasn't initially declared and assigned, we wouldn't be able to compile,
    WhatTheFunc<string, string, int, int> b = _ => c;   // since the second functon refers to the first (and the third to the second, etc).
    WhatTheFunc<int, string, string, int> a = _ => b;   // It is only after the rest of the cycle has been declared and assigned, that we can
    Foo = _ => a;                                       // assign the first function its real value (which is to return the fourth function).
    
    // Compiles and runs
    Foo(0)(1)("two")("three")(4)(5)("six")("seven")(8)(9)("ten!");
    
    // None of these compile (they have the wrong pattern of argument types)
    // Foo("0")(1)("two")("three")(4)(5)("six")("seven")(8)(9)("ten!");
    // Foo(0)("1")("two")("three")(4)(5)("six")("seven")(8)(9)("ten!");
    // Foo(0)(1)(2)("three")(4)(5)("six")("seven")(8)(9)("ten!");
    // Foo(0)(1)("two")(3)(4)(5)("six")("seven")(8)(9)("ten!");
    // Foo(0)(1)("two")("three")("4")(5)("six")("seven")(8)(9)("ten!");
    // Foo(0)(1)("two")("three")(4)("5")("six")("seven")(8)(9)("ten!");
    // Foo(0)(1)("two")("three")(4)(5)(6)("seven")(8)(9)("ten!");
    // Foo(0)(1)("two")("three")(4)(5)("six")(7)(8)(9)("ten!");
    // Foo(0)(1)("two")("three")(4)(5)("six")("seven")("8")(9)("ten!");
    // Foo(0)(1)("two")("three")(4)(5)("six")("seven")(8)("9")("ten!");
    // Foo(0)(1)("two")("three")(4)(5)("six")("seven")(8)(9)(10);
}

// Golf Version - 249 characters, including 62 characters from original problem:
delegate R<U,V,W,T> R<T,U,V,W>(T _);void F(){R<int,int,string,string> Foo=null;R<string,int,int,string> c=_=>Foo;R<string,string,int,int> b=_=>c;R<int,string,string,int> a=_=>b;Foo=_=>a;Foo(0)(1)("two")("three")(4)(5)("six")("seven")(8)(9)("ten!");}