Erlang 8.11.2.3 first step (no counter and refactored)

gistfile1.erl

-module(ring2).
-export([start/1]).

start(Msg) ->
    Pid1 = ring(),
    Pid2 = ring(),
    Pid3 = ring(),
    Pid4 = ring(),
    shackle(Pid1, Pid2),
    shackle(Pid2, Pid3),
    shackle(Pid3, Pid4),
    shackle(Pid4, Pid1),
    send(Pid1, Msg).

shackle(LPid, RPid) ->
    LPid ! {connect, LPid, RPid}.

ring() ->
    spawn(fun() -> loop(0,0) end).

send(StartPid, Msg) ->
    StartPid ! {send, Msg}.

loop(LPid, RPid) ->
    receive
        {connect, Left, Right} ->
            io:format("shackle connected~n"),
            loop(Left, Right);
        {send, Msg} ->
            io:format("Message sent: ~p~n", [RPid]),
            RPid ! {send, Msg},
            loop(LPid, RPid)
    end.