This paper investigates one high school student's use of gestures in an interview context in which he worked on the problem of understanding graphical representations of motion. The goal of the investigation was to contribute a detailed analysis of the process of learning as it occurred over a short time period in order to contribute to the broader understanding of the role of the body in the development of new knowledge in mathematics. In particular, the paper addresses the following questions: (1) How might students make the link between powerful understanding of visual attributes of graphs and the bodily experiences of creating graphs of their own motions?; and (2) How can the dynamic nature of gestures help students understand the dynamic nature of graphs of motion? (SOE)