Do you remember those games on the back of cereal boxes when you were a kid? While shoveling your favorite sugary cereal in your mouth on a lazy Saturday morning, you could analyze two pictures that looked identical at first glance. But the challenge was to spot the differences. The house on the left had two-paned windows, while the house on the right had single-pane windows. The tree on the right was filled with apples while the tree on the left was empty.