I don't remember having so much fun reading a book as this one. While the author is much better at math than I ever hope to be, his line of thought is so similar to that of any boy who has played with these toys ( so loved by every male child from the cradle to the grave), that you are drawn into a conspiracy with him to make it " shoot harder', "shoot farther", just better than the last one you made! The underlying humor, is obvious to anyone who's done such experiments.