For a strange reason that I don't know, someone ask to me to implement in a financial application the Fibonacci Sequence.
First of all, I don't know this mathematical role, because I hate this subject!
I seek some information about Fibonacci and this role over Internet and the best information that I found is on wikipedia.
There is a simple way to find and display the number of Fibonacci sequence in C#.

Here, I write the function in C#:

        class Program
        {
            static double FibonacciSequence(double x)
            {
                if (x <= 1) return 1;
                return FibonacciSequence(x - 1) + FibonacciSequence(x - 2);
        }

        static void Main()
        {
                for (int i = 0; i <= 40; i++)
                {
                    Console.WriteLine("Fibonacci number: {0}", FibonacciSequence(i));
                }
                Console.WriteLine("Finished.");
                Console.ReadKey();
            }
        }

and in Vb.net:

    Class Program
        Private Shared Function FibonacciSequence(ByVal x As Double) As Double
            If x <= 1 Then
                Return 1
            End If
            Return FibonacciSequence(x - 1) + FibonacciSequence(x - 2)
        End Function
    
        Private Shared Sub Main()
            For i As Integer = 0 To 40
                Console.WriteLine("Fibonacci number: {0}", FibonacciSequence(i))
            Next
            Console.WriteLine("Finished.")
            Console.ReadKey()
        End Sub
    End Class

A StopWatch class can measure elapsed time for one interval.
We can use for measuring performance of the new code blocks or algorithms.

Use IsRunning method to determine the state of StopWatch object.
Use Start method to begin measuring elapsed time, and Stop method to stop measuring elapsed time.

        {
            Stopwatch stopwatch = new Stopwatch();
            stopwatch.Start();
            textBox1.Text = DateTime.Now.TimeOfDay.ToString();
            Application.DoEvents();

            // Perform a long process
            Thread.Sleep(34564);

            stopwatch.Stop();
            textBox2.Text = DateTime.Now.TimeOfDay.ToString();
            textBox3.Text = stopwatch.Elapsed.Milliseconds.ToString();
            Application.DoEvents();
        }

You can find an example application in the attached file.