2
5 2 #
11 1 !

#      # #      #
##    ## ##    ##
# #[]# # # #[]# #
##    ## ##    ##
#      # #      #

!            !
!!          !!
! !        ! !
!  !      !  !
!   !    !   !
!    ![]!    !
!   !    !   !
!  !      !  !
! !        ! !
!!          !!
!            !

import java.util.*;

public class Main
{
    public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);

        int sets, width, bowties, length, intspaces, extspaces, mid, counter;
        char mat;

        sets = in.nextInt();
        for(int i = 1; i <= sets; i++)
        {
            length = in.nextInt();
            bowties = in.nextInt();
            mat = in.next().charAt(0);
            width = length + 3;
            mid = length/2 + 1;
            counter = 2;
            String[] out = new String[length];


            for(int x = 0; x < mid; x++)
            {
                if(x == 0)
                {
                  intspaces = width - 2;
                  String intspace = space(intspaces, length);
                  out[x] = mat + intspace + mat;
                }
                else if(x != (mid-1))
                {
                  intspaces = width - 2 * (x + 1);
                  extspaces = x - 1;
                  String intspace = space(intspaces, length);
                  String extspace = space(extspaces, length);
                  out[x] = mat + extspace + mat + intspace + mat + extspace + mat;
                }
                else
                {
                  extspaces = x - 1;
                  String extspace = space(extspaces, length);
                  out[x] = mat + extspace + mat + "[]" + mat + extspace + mat;
                }
            }

            for(int x = mid; x < length; x++)
            {
              int count = x - counter;
              out[x] = out[count];
              counter += 2;
            }

            if(bowties != 1)
            {
            stringMulti(out, length, width, bowties);
            }

            for(int x = 0; x < length; x++)
            {
              System.out.println(out[x]);
            }
            System.out.println();

        }
    }
    public static String space(int spaces, int length)
    {
        StringBuilder sb = new StringBuilder(length - 2);
        for(int i = 1; i <= spaces; i++)
        {
            sb.append(" ");
        }
        return sb.toString();
    }

    public static void stringMulti(String out[], int length, int width, int sets)
    {
      for(int x = 0; x < length; x++)
      {
        StringBuilder sb = new StringBuilder(width + sets * (width + 1));
        sb.append(out[x]);
        for(int y = 1; y < sets; y++)
        {
       sb.append(" ");
       sb.append(out[x]);
        }
        out[x] = sb.toString();
      }

    }
}