Someone

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication4 {
    class Program {
        static void Main( string[] args ) {
            Console.Write( "Enter a String : " );
            string text = Console.ReadLine();
            Console.Write( "How many rows: " );
            int rows = int.Parse( Console.ReadLine() );
            Console.Write( "How many columns: " );
            int cols = int.Parse( Console.ReadLine() );
            Console.WriteLine( rows + "x" + cols );
            char[] ctext = text.ToCharArray();
            Random r = new Random();
            int rn;
            for ( int n = 0; n < cols; n++ ) {
                rn = r.Next( text.Length );
                Console.Write( ctext[rn] );
                for ( int m = 0; m < rows; m++ ) {
                    rn = r.Next( text.Length );
                    Console.Write( ctext[rn] );
                }
                Console.Write( "\n" );
            }
        }
    }
}