static void Main(string[] args) { Subject TheSubject = new Subject(); List <IObserver> mySubs = new List <IObserver> { new Observer(TheSubject), new Observer(TheSubject) }; ConsoleKeyInfo myKey; Console.Title = "Press E to escape"; do { foreach (IObserver current in mySubs) { Console.WriteLine("Unique ID: " + current.GetHashCode().ToString().Substring(0, 4) + " "); TheSubject.callMethod(); Console.WriteLine(); } Console.WriteLine(); myKey = Console.ReadKey(); } while (myKey.Key != ConsoleKey.E); Console.ReadLine(); }