[seimur]

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

namespace Equation
{
class Program
{
const char DBL_VLINE = '║';
const char DBL_HLINE = '═';
const char DBL_LUCORNER = '╔';
const char DBL_LDCORNER = '╚';
const char DBL_RUCORNER = '╗';
const char DBL_RDCORNER = '╝';

static void Main(string[] args)
{
int width = 50, height = 20;
int sx = (Console.WindowWidth - width) / 2;
int sh = (Console.WindowHeight - height) / 2;

Console.CursorTop = sh; Console.CursorLeft = sx;
Console.Write(DBL_LUCORNER);
Console.CursorTop = sh; Console.CursorLeft = sx + width - 1;
Console.Write(DBL_RUCORNER);
Console.CursorTop = sh + height - 1; Console.CursorLeft = sx;
Console.Write(DBL_LDCORNER);
Console.CursorTop = sh + height - 1; Console.CursorLeft = sx + width - 1;
Console.Write(DBL_RDCORNER);

// Draw horizontal lines.
for (int i = 0; i < width - 2; i++)
{
Console.CursorTop = sh;
Console.CursorLeft = sx + 1 + i;
Console.Write(DBL_HLINE);

Console.CursorTop = sh + height - 1;
Console.CursorLeft = sx + 1 + i;
Console.Write(DBL_HLINE);
}

// Draw vertical lines.
for (int i = 0; i < height - 2; i++)
{
Console.CursorTop = sh + 1 + i;
Console.CursorLeft = sx;
Console.Write(DBL_VLINE);

Console.CursorTop = sh + 1 + i;
Console.CursorLeft = sx + width - 1;
Console.Write(DBL_VLINE);
}

Console.WriteLine("\n\n\n");
}
}
}