This analysis of a problem that is frequently posed at professional development workshops, in print, and on the Web--the coffee-milk mixture riddle--illustrates the timeless advice of George Pólya's masterpiece on problem solving in mathematics, "How to Solve It." In his book, Pólya recommends that problems previously solved and put aside should be revisited in order to consolidate a student's knowledge and develop the ability to solve problems. This article describes how revisiting a problem created new questions and provided insight into examining a solution in multiple ways.