private bool CheckColliding()
 {
     if (bird.Top <= 0 || bird.Bottom >= this.Height)
     {
         return(true);
     }
     foreach (Control control in this.Controls)
     {
         if (control is Tube)
         {
             if (bird.colliding(control))
             {
                 return(true);
             }
         }
     }
     return(false);
 }