Почему графика тормозит компьютер

using System; //circle.cs
using System.Drawing;
using System.Windows.Forms;
 
class circle: Form
{ public static void Main()
    { Application.Run(new circle());}
public circle()
    { Text = "circle";
      BackColor = System.Drawing.Color.Blue;
      ForeColor = System.Drawing.Color.Red;
      ResizeRedraw = true;
      Width = 600; 
      Height = 360;
    }
    protected override void OnPaint(PaintEventArgs dan)
    { Pen pen = new Pen(ForeColor);
 
Graphics dav = dan.Graphics;
SolidBrush BlueBrush = new SolidBrush(Color.Blue);
dav.FillRectangle(BlueBrush, 0, 120, 600, 200);
 
for (int k = 1; k <=5; k++)
    for (int x = -50; x <=50; x++)
        { int y=0;
          dav.DrawEllipse(new Pen(Color.Magenta, 3), x*k+195, 225, 10, -80);
          if (x< 50) y=-x/5;
          if (x< 25) y= x/5;
          if (x<-25) y=-x/5;
          if (x<-50) y= x/5;
 
          System.Threading.Thread.Sleep(10);
          dav.DrawEllipse(new Pen(Color.Orange, 3), x*k+195, 225, 10, -80);
        }
    }
}

dav.DrawLine(pred, new Point(30+20*x+20*y, 400-20*y-a[x,y]), new Point(30+20*(x+1)+20*y, 400-20*y-a[x+1, y]));

dan.Graphics.DrawLine(pblu, i*s+c, j*s+d, i*s+c+1, j*s+d+1);

using System; using System.Drawing; // SUMCOMB.cs
using System.Windows.Forms; namespace SUMCOMB
{ public class Program
{ static void Main() { Application.Run(new SUMCOMB()); }}
class SUMCOMB : Form
{ ComboBox comboBoxD; TextBox textBoxA; Button buttonV;
 
public SUMCOMB()
{ var labelD = new Label(); labelD.Text = "D СТРОК";
  labelD.Location = new System.Drawing.Point(45, 28);
  Controls.Add(labelD);
 
comboBoxD = new ComboBox();
    comboBoxD.Location = new Point(45, 50);
    comboBoxD.Width = 50;
    comboBoxD.Items.Add("7");
    comboBoxD.Items.Add("5");
    comboBoxD.Items.Add("3");
    comboBoxD.SelectedIndex = 1;
    this.Controls.Add(comboBoxD);
 
var labelA = new Label(); labelA.Text = "A СТОЛБЦОВ";
    labelA.Location = new System.Drawing.Point(45, 78);
    Controls.Add(labelA);
 
textBoxA=new TextBox(); textBoxA.Text = "4";
    textBoxA.Location = new System.Drawing.Point(45, 100);
    this.Controls.Add(textBoxA);
 
buttonV = new Button();   
    buttonV.Location = new System.Drawing.Point(45, 200);
    buttonV.Text = "SUMCOMB";
    buttonV.Click+=buttonV_Click; Controls.Add(buttonV);
}
 
private void buttonV_Click(object sender, EventArgs e)
{ int dd = int.Parse(comboBoxD.Text);
  int aa = int.Parse(textBoxA.Text);
 
for (int i=1; i <= dd; i++)
{ string s= "";
    for (int j=1; j <= aa; j++)
    s = s+"  "+(i+j).ToString();
var labelI = new Label();
labelI.Text = s;
labelI.Location = new System.Drawing.Point(145, 25+25*i);
Controls.Add(labelI);
}}}}

using System; using System.Drawing; // SOEDIN.cs
using System.Windows.Forms; class SOEDIN 
{ Timer timer; Form form;
int[] x = new int[10]; int[] y = new int[10];
    
static void Main(string[] args) 
 { var p = new SOEDIN();
 }
 
public SOEDIN()
{ form = new Form() 
{ Text = "SOEDIN", Width = 600, Height = 360 };
 
timer = new Timer() { Interval = 2000 };
timer.Tick += delegate(object sender, EventArgs e)
 
{ Random rand = new Random();
 
for (int i = 1; i <=8; i++)
   { x[i]=50+rand.Next(400);
     y[i]=50+rand.Next(200);
   }
 
Graphics f = Graphics.FromHwnd(form.Handle);
f.Clear(Color.Green);
Graphics w = Graphics.FromHwnd(form.Handle);
 
for (int i = 1; i <=8; i++)
w.DrawEllipse(new Pen(Color.Magenta, i), x[i]-10, y[i]-5, 20, 10);
 
for (int i = 1; i < 8; i++)
    for (int j = 8; j > i; j--)
{ Bitmap dblBuffer = new Bitmap(form.Width, form.Height);
Graphics g = Graphics.FromImage(dblBuffer);
g.DrawLine(new Pen(Color.Red, i), new Point(x[i], y[i]), new Point(x[j], y[j]));//Pens.Red
f.DrawImage(dblBuffer, new Point(0, 0));
System.Threading.Thread.Sleep(200);
}
System.Threading.Thread.Sleep(500);
Array.Clear(x, 0, 10); Array.Clear(y, 0, 10);
     };
timer.Start();
Application.Run(form);
   }     
}