Numbers Arranged As Spiral

/*
 * * Write a program that reads a positive integer number N (N < 20) from console and outputs in the console the numbers 1 ... N numbers arranged as a spiral.
        Example for N = 4
 *
*/

using System;

class NumbersArrangedAsSpiral
{
    static void Main()
    {
        byte numberN;

        string invalidInput = "Please enter a valid number 0 < N < 20!" + Environment.NewLine;
        Console.WriteLine("Enter a value for N:");
        while (!(byte.TryParse(Console.ReadLine(), out numberN) && numberN > 0 && numberN < 20))
        {
            Console.WriteLine(invalidInput);
            Console.WriteLine("Enter a value for N:");
        }
        Console.WriteLine();

        int[,] spiralMatrix = new int[numberN, numberN];
        byte rows = 0;
        byte columns = 0;
        int elementsCount = 0;
        byte currentRow = 0;
        byte currentColumn = 0;
        int maxRows = numberN - 1;
        int maxColumns = maxRows;

        while (!(elementsCount >= numberN * numberN))
        {
            for (int i = currentColumn; i <= maxColumns; i++)
            {
                elementsCount++;
                spiralMatrix[currentRow, i] = elementsCount;
            }
            currentRow++;
            for (int i = currentRow; i <= maxRows; i++)
            {
                elementsCount++;
                spiralMatrix[i, maxColumns] = elementsCount;
            }
            maxColumns--;
            for (int i = maxColumns; i >= currentColumn; i--)
            {
                elementsCount++;
                spiralMatrix[maxRows, i] = elementsCount;
            }
            maxRows--;
            for (int i = maxRows; i >= currentRow; i--)
            {
                elementsCount++;
                spiralMatrix[i, currentColumn] = elementsCount;
            }
            currentColumn++;
        }

        for (rows = 0; rows < numberN; rows++)
        {
            for (columns = 0; columns < numberN; columns++)
            {
                Console.Write("{0,5}", spiralMatrix[rows, columns]);
            }
            Console.WriteLine();
        }
        Console.WriteLine();
        Main();
    }
}