{

ConcreteSubjectSync a;

ConcreteObserver<ConcreteSubjectSync> b("1", &a), b2("2", &a), b3("3", &a), b4("4", &a);

a.on_none();

a.on_coordinate_changed(1.0f, 1.0f, 2.0f);

b2.detach(&a);

a.on_state(2);

a.on_error(-8);

ConcreteSubjectAsync a2(3U);

ConcreteObserver<ConcreteSubjectAsync> c("A", &a2), c2("B", &a2), c3("C", &a2), c4("D", &a2);

a2.on_none();

a2.on_coordinate_changed(1.0f, 1.0f, 2.0f);

c4.detach(&a2);

a2.on_state(2);

a2.on_error(-8);

std::this_thread::sleep_for(std::chrono::seconds(1));

return 0;

}