/// <summary>
        /// Selects meat type and updates image
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void MeatRadioButtons_Click(object sender, EventArgs e)
        {
            CustomPizza pizza = (CustomPizza)currentPizza;

            if (sender == chickenRadioButton)
            {
                pizza.PizzaMeat = CustomPizza.Meat.Chicken;
            }

            else if (sender == sausageRadioButton)
            {
                pizza.PizzaMeat = CustomPizza.Meat.Sausage;
            }

            else if (sender == beefRadioButton)
            {
                pizza.PizzaMeat = CustomPizza.Meat.Beef;
            }

            else
            {
                pizza.PizzaMeat = CustomPizza.Meat.Pepperoni;
            }

            // update image
            pizza.AddTopping(pizza.PizzaMeat);
            orderPictureBox.Image = pizza.GetImage();
        }
        /// <summary>
        /// Selects which side of pizza to apply veggie topping and updates image
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void VeggiesSizeImages_Click(object sender, EventArgs e)
        {
            CustomPizza pizza = (CustomPizza)currentPizza;

            if (sender == veggiesLeftPicturebox)
            {
                pizza.VeggiesSide = CustomPizza.Side.Left;

                // update side images
                veggiesLeftPicturebox.Image   = Constants.ButtonLeftSelected;
                veggiesMiddlePictureBox.Image = Constants.ButtonWhole;
                veggiesRightPicturebox.Image  = Constants.ButtonRight;
            }

            else if (sender == veggiesRightPicturebox)
            {
                pizza.VeggiesSide = CustomPizza.Side.Right;

                // update side images
                veggiesLeftPicturebox.Image   = Constants.ButtonLeft;
                veggiesMiddlePictureBox.Image = Constants.ButtonWhole;
                veggiesRightPicturebox.Image  = Constants.ButtonRightSelected;
            }

            else
            {
                pizza.VeggiesSide = CustomPizza.Side.Both;

                // update side images
                veggiesLeftPicturebox.Image   = Constants.ButtonLeft;
                veggiesMiddlePictureBox.Image = Constants.ButtonWholeSelected;
                veggiesRightPicturebox.Image  = Constants.ButtonRight;
            }

            // update image
            pizza.AddTopping(pizza.PizzaVeggies);
            orderPictureBox.Image = pizza.GetImage();
        }
        /// <summary>
        /// Selects which size of pizza to apply topping and updates image
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void MeatSideImages_Click(object sender, EventArgs e)
        {
            CustomPizza pizza = (CustomPizza)currentPizza;

            if (sender == meatLeftPictureBox)
            {
                pizza.MeatSide = CustomPizza.Side.Left;

                // update side images
                meatLeftPictureBox.Image   = Constants.ButtonLeftSelected;
                meatMiddlePicturebox.Image = Constants.ButtonWhole;
                meatRightPicturebox.Image  = Constants.ButtonRight;
            }

            else if (sender == meatRightPicturebox)
            {
                pizza.MeatSide = CustomPizza.Side.Right;

                // update side images
                meatLeftPictureBox.Image   = Constants.ButtonLeft;
                meatMiddlePicturebox.Image = Constants.ButtonWhole;
                meatRightPicturebox.Image  = Constants.ButtonRightSelected;
            }

            else
            {
                pizza.MeatSide = CustomPizza.Side.Both;

                // update side images
                meatLeftPictureBox.Image   = Constants.ButtonLeft;
                meatMiddlePicturebox.Image = Constants.ButtonWholeSelected;
                meatRightPicturebox.Image  = Constants.ButtonRight;
            }

            pizza.AddTopping(pizza.PizzaMeat);

            orderPictureBox.Image = pizza.GetImage();
        }
        /// <summary>
        /// Selects veggie type and updates image
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void VeggiesRadioButtons_Click(object sender, EventArgs e)
        {
            CustomPizza pizza = (CustomPizza)currentPizza;

            if (sender == mushroomsRadioButton)
            {
                pizza.PizzaVeggies = CustomPizza.Veggies.Mushrooms;
            }

            else if (sender == broccoliRadioButton)
            {
                pizza.PizzaVeggies = CustomPizza.Veggies.Broccoli;
            }

            else
            {
                pizza.PizzaVeggies = CustomPizza.Veggies.Spinach;
            }

            // update image
            pizza.AddTopping(pizza.PizzaVeggies);
            orderPictureBox.Image = pizza.GetImage();
        }