I first met C.C. Li when I was a graduate student at UCLA and C.C. teaching a course in Population Genetics as a visiting scholar. While his class was very good and I learned a lot, I had no idea that later I would be fortunate enough to come to Pittsburgh to his department.
Shortly after my arrival in Pittsburgh in the early 1990's, I had the pleasure of working with C.C. on a paper dealing with the probability of a random match between the two DNA profiles of a pair of individuals. The mathematics was challenging, and it was difficult to visualize exactly what was going on in our multidimensional model. Then, one morning, C.C. came into my office with an elegant three-dimensional paper model that he had made that provided great insight into the properties of our model. I kept this wonderful paper model on top of my computer monitor for many years as a gentle reminder that the best mathematical modeling often results from sharp intellectual insight, rather than from extensive computer-based simulations.