private static void Main(string[] args)
        {
            var rectangulos = new[]
            {
                new Principal {
                    Ancho = 10, Alto = 5
                },
                new Principal {
                    Ancho = 5, Alto = 1
                }
            };

            var sumaDeAreas      = Rectangulo.SumAreas(rectangulos);
            var sumaDePerimetros = Rectangulo.SumPerimetro(rectangulos);

            Console.WriteLine($"Area total: {sumaDeAreas}" +
                              $"\nPerimetro total: {sumaDePerimetros}");
            Console.ReadKey();
        }