Traversing a two Dimensional Array

This was a challenge... But I got it:

---

using System;

namespace reverse
{
    class Program
    {
        static void Main(string[] args)
        {
            int[,] matrix = new int[,] { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 9, 10 }, { 11, 12, 13, 14, 15 }, { 16, 17, 18, 19, 20 } };
            int rows = matrix.GetLength(0);
            int cols = matrix.GetLength(1);
            int r = 0, c = 0;

            if (rows < 2 || cols < 2)
                foreach (int i in matrix)
                    Console.WriteLine(i);
            else
            {
                for (int i = 0; i < rows / 2; i++)
                {
                    for (c = i; c < cols - i - 1; c++)
                        Console.WriteLine(matrix[i, c]);
                    for (r = i; r < rows - i - 1; r++)
                        Console.WriteLine(matrix[r, c]);
                    for (; c > i; c--)
                        Console.WriteLine(matrix[r, c]);
                    for (; r > i; r--)
                        Console.WriteLine(matrix[r, c]);
                }

                if (rows % 2 != 0)
                    for (; 2 * c < cols; c++)
                        Console.WriteLine(matrix[r, c]);
            }

            Console.ReadLine();
        }
    }
}

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What is done is that one turn around is being repeated a couple of times (depending of the number of rows) and then if the number of rows is odd (there's still a possibility that there's a number in the middle) it displays the middle row.

EDIT: It doesn't work for an array with only one row or column...fixed