public void Clear()
 {
     if (!Play)
     {
         while (SystemCircle.Count > 0)
         {
             SystemCircle.RemoveCircle(SystemCircle.GetCircle(0));
         }
         lastTrail = null;
         GC.Collect();
     }
 }
 private void DeleteButton_Click(object sender, EventArgs e)
 {
     systemCircle.RemoveCircle(systemCircle.GetCircle(comboBox.SelectedIndex));
     UpdateComboBox();
 }