Фрактал дракон программа С#

using  System;
 using  System.Collections.Generic;
 using  System.ComponentModel;
 using  System.Data;
 using  System.Drawing;
 using  System.Text;
 using  System.Windows.Forms;


 namespace  lab1
{
     public   partial   class  Form1 : Form
    {
         int  k1 = 0;
        Pen h =  new  Pen(Color.Red, 1);
        Color c =  new  Color();
         const   int  bm_width = 300, bm_height = 300;
         static  Bitmap bm =  new  Bitmap(bm_width, bm_height);
        Graphics gg = Graphics.FromImage(bm);
         public  Form1()
        {
            InitializeComponent();
        }
     
         private   void  paaint( int  x1, int  y1, int  x2, int  y2, int  k)
        {
           
             int  tx, ty;
             if  (k == 0)
            {
                gg.DrawLine(h, x1, y1, x2, y2);
                 return ;
            }
            
                tx = (x1 + x2) / 2 + (y2 - y1) / 2;
                ty = (y1 + y2) / 2 - (x2 - x1) / 2;
                paaint(x2, y2, tx, ty, k - 1);
                paaint(x1, y1, tx, ty, k - 1);
                pictureBox1.Image = bm;
            
            
        }

         private   void  button1_Click_1( object  sender, EventArgs e)
        {
            gg.Clear(Color.White);
            k1 = Convert.ToInt32(textBox1.Text);
             if  (k1 >= 14)
            {
                MessageBox.Show( "Введите меньшее значение шагов :)" );
            }
             else 
            {
                
                 int  x1 = 200, y1 = 200, x2 = 100, y2 = 100;
                paaint(x1, y1, x2, y2, k1);
            }
        }


    }
}