class TrafficLight
    {
        private int size;
        private Color color;

        public TrafficLight(int s, Color c)
        {
            color = c;
            size = s;
        }

        public int Size
        {
            get
            {
                return size;
            }

            set
            {
                if (size >= 5 && size <= 75)
                    size = value;
            }
        }

        public void ChangeColor()
        {
            if (color == Color.Red)
            {
                color = Color.Green;
            }
            else if (color == Color.Green)
            {
                color = Color.Orange;
            }
            else if (color == Color.Orange)
            {
                color = Color.Red;
            }
        }

        public void Draw(Graphics gr)
        {
            if (color == Color.Red)
            {
                gr.FillEllipse(Brushes.Red, 10, 10, size, size);
                //The format of the integers is x, y, width, height
                //So because the first circle has y = 10, the second will be 10 + size and will be placed below the first one
                gr.FillEllipse(Brushes.White, 10, 10 + size, size, size);
                //the third circle will be 10 + 2 * size
                gr.FillEllipse(Brushes.White, 10, 10 + 2 * size, size, size);
            }
            else if (color == Color.Orange)
            {
                // red circle spot
                gr.FillEllipse(Brushes.White, 10, 10, size, size);
                //orange circle
                gr.FillEllipse(Brushes.Orange, 10, 10 + size, size, size);
                // green circle spot
                gr.FillEllipse(Brushes.White, 10, 10 + 2 * size, size, size);
            }
            else if (color == Color.Green)
            {
                // green cicrle
                gr.FillEllipse(Brushes.Green, 10, 10 + 2 * size, size, size);
                // red circle spot
                gr.FillEllipse(Brushes.White, 10, 10, size, size);
                // orange circle spot
                gr.FillEllipse(Brushes.White, 10, 10 + size, size, size);
            }
        }
    }
}