One91

 public static void Main(string[] args)  
     {  
       for (int i = 1; i <= 5; i++)  
       {  
         for (int j = 1; j <= i; j++)  
         {  
           Console.Write("" + (j));  
         }  
         Console.WriteLine("");  
       }  
       for (int k = 4; k >= 0; --k)  
       {  
         for (int j = 1; j <= k; j++)  
         {  
           Console.Write("" + (k));  
         }  
         Console.WriteLine("");  
       }  
       Console.ReadLine();  
     }