Occasionally engineering provides me with startling perspectives on art. This happened for me with the third book in the Harry Potter series, the Prisoner of Azkaban, generally acknowledged to be the most accomplished of the series. Critics make a compelling case that among the movies too, Alfonso Cuaron’s treatment of this book has been the best of the lot so far, and better than even the book itself. So let me offer you a perspective on why the third book and movie are great, based on an ...