using System;

using System.Collections.Generic;

using System.Text;

using static System.Console;

public class Program

{

    public static void Main()

    {

        var alphabet = new List<char>();

        for (int i = 0; i < 26; i++)

        {

            alphabet.Add((char)('A' + i));  

        }

        foreach (char c in alphabet)

        {

            WriteLine(Diamond.Make(c));

        }

    }

}

​

public static class Diamond

{

 public static string Make(char target)

 {

     if (target < 'A' || target > 'Z')

         throw new ArgumentOutOfRangeException(nameof(target), "Target must be between 'A' and 'Z'.");

​

     var sb = new StringBuilder();

     int size = target - 'A';

     for (int i = 0; i <= size; i++)

     {

         sb.AppendLine(DrawLine(size - i, (char)('A' + i), i));

     }

     for (int i = size - 1; i >= 0; i--)

     {

         sb.AppendLine(DrawLine(size - i, (char)('A' + i), i));

     }

​

     return sb.ToString();

 }

​

 private static string DrawLine(int padding, char letter, int innerSpace)

 {

     var sb = new StringBuilder();

​

     sb.Append(new string('·', padding));

     sb.Append(letter);

     if (innerSpace > 0)

     {

         sb.Append(new string('·', innerSpace * 2 - 1));

         sb.Append(letter);

     }

​

     sb.Append(new string('·', padding));

     return sb.ToString();

 }

}