using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var m = new[,] {

            { 1, 2, 3 },

            { 4, 5, 6 },

            { 7, 8, 9 } };

        var m2 = new[,] {

            { 1, 2, 3, 4 },

            { 5, 6, 7, 8 },

            { 9,10,11,12 },

            {13,14,15,16 } };

        IterateMatrixInSpiralOrder(m2);

    }

​

    public static void IterateMatrixInSpiralOrder(int[,] m)

    {

        var size = m.GetLength(0);

        var start = 0;

        for (var i = size; i > 0; i-=2)

        {

            SpiralIterationStep(m, start, start, i - 1);

            start++;

        }

    }

    private static void SpiralIterationStep(int[,] m, int startX, int startY, int stepLen)

    {

        if (stepLen == 0) Console.WriteLine(m[startX, startY]);

        for (var i = startX; i < startX + stepLen; i++) Console.WriteLine(m[startY          , i]);

        for (var i = startY; i < startY + stepLen; i++) Console.WriteLine(m[i               , startX + stepLen]);

        for (var i = startX + stepLen; i > startX; i--) Console.WriteLine(m[startY + stepLen, i]);    

        for (var i = startY + stepLen; i > startY; i--) Console.WriteLine(m[i               , startX]);    

    }

}