At the beginning of a visualization course, it can be challenging to provide simple, practical exercises that allow students to explore the benefits and constraints of different visual mappings. We present an interactive teaching exercise, adapted from the VizKit visualization workshop, that can help illustrate and encourage critical thinking about basic visualization concepts. In this paper we present the unique pedagogical goals and practical challenges associated with using construction exercises in an undergraduate course. We further describe how we modified VizKit for use in a classroom setting , introducing new exercises and construction materials. Finally we reflect on the observations gathered during an initial in-class deployment with 28 students.