static void Main() { Shape recti = new Rectangle(2, 5); Console.WriteLine(recti.Surface()); ISurface[] surfaces = new ISurface[] { new Rectangle(5, 8.9), new RightAngleTriangle(3.6, 2.3), new Square(7), new RightAngleTriangle(78, 90.6), new Rectangle(56, 89.2) }; foreach (ISurface item in surfaces) { Console.WriteLine(item.Surface()); } }