using System.Windows.Forms;
using System.Drawing;
using System;

public class Test : Form
{
   public Test()
   {
      Size   = new Size(500, 500);
      Paint += new PaintEventHandler(DoRender);

      mTimer.Tick += new System.EventHandler(
         delegate { if(++mDegrees == 360) mDegrees = 0; Refresh(); }
      );

      mTimer.Interval = 25;
      mTimer.Enabled  = true;
   }

   private void DoRender(object sender, PaintEventArgs e)
   {
      e.Graphics.Clear(BackColor);

      int xCenter = ClientSize.Width  / 2;
      int yCenter = ClientSize.Height / 2;

      int radius = (int)(.8 * Math.Min(xCenter, yCenter) + 0.5);

      int xFirst = 0, yFirst = 0, xOld = 0, yOld = 0;

      for(int i = 0, degrees = mDegrees; i < N_SIDES; i ++, degrees += STEP)
      {
         double angle = degrees * (Math.PI / 180.0);

         int x = (int)Math.Round(xCenter + radius * Math.Cos(angle));
         int y = (int)Math.Round(yCenter + radius * Math.Sin(angle));

         if(i == 0)
         {
            xFirst = x;
            yFirst = y;
         }
         else
         {
            e.Graphics.DrawLine(Pens.Black, x, y, xOld, yOld);

            if(i + 1 == N_SIDES)
               e.Graphics.DrawLine(Pens.Black, x, y, xFirst, yFirst);
         }

         xOld = x;
         yOld = y;
      }
   }

   private const int N_SIDES = 5;
   private const int STEP    = (360 / N_SIDES);

   private int   mDegrees = 0;
   private Timer mTimer   = new System.Windows.Forms.Timer();

   static void Main()
   {
      Application.Run(new Test());
   }
}