%% fib2.erl

-module(fib2).
-export([fib/1]).

fib(0) -> 0;
fib(1) -> 1;
fib(N) ->
    fib2(N - 1) + fib(N - 2).

fib2(N) ->
    Pid = spawn(fun worker/0),
    Pid ! {self(), N},
    receive
        F -> F
    end.

worker() ->
    receive
        {From, N} -> From ! fib(N)
    end.