interface ihello {
  out void world();
  
  behaviour {
    on inevitable: world;
  }
}

interface iworld {
  in void hello();
  out void sunrise();
  out void cruel();
  out void world();
  
  behaviour {
    on hello: { cruel; world;}
    on inevitable: sunrise;
  }
}

component hello_flush {
  provides ihello h;
  requires iworld w;
  
  behaviour {
    on w.sunrise(): w.hello();
    on w.cruel(): h.world();
    on w.world(): {}
  }
}