Modules for demo

-module(demo).
-export([add/2, subtract/2]).

add(N1, N2) ->
	N1 + N2.

subtract(N1, N2) ->
	N1 - N2.

-module(demo_send).
-export([send_to_self/1]).

send_to_self(Msg) ->
    self() ! Msg.