Elixir short sample.

count.exs

defmodule Count do
  def f parent, cnt do
    send parent, {:print, cnt}
    receive do
      :up -> Count.f parent, cnt + 1
      _   ->
        send parent, {:print, "バカ"}
        Count.f parent, cnt
    end
  end
end

defmodule Main do
  def start do
    pid = spawn Count, :f, [self(), 0]
    Main.loop pid
  end

  def loop pid do
    send pid, :up
    receive do
      {:print, n} ->
        IO.puts n
        Main.loop pid
      _ ->
        IO.puts "アホ"
        Main.loop pid
    after 1000 ->
      IO.puts "tick"
      Main.loop pid
    end
  end
end

Main.start