echo.erl

-module(echo).                       
-export([go/0]).                     
                                     
go() ->                              
  Pid2 = spawn(fun() -> loop() end), 
  Pid2 ! {self(), hello},            
                                     
  receive
                                                                              
    {Pid2, Msg} ->                   
      io:format("P1 ~w~n",[Msg])     
                                     
  end,                               
  Pid2 ! stop.                       
                                     
loop() ->                            
  receive                            
    {From, Msg} ->                   
      From ! {self(), Msg},          
      loop();                        
    stop -> true                     
  end.