private static void startEffect()
 {
     if (knightRider != null)
     {
         knightRider.start();
     }
     else
     {
         knightRider = new KnightRider(effectColor, bgColor, rows);
     }
 }
 private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
 {
     stopEffect();
     knightRider = null;
 }