I present a flip book exercise wherein participants draw and animate two flip books. The first is an animation of a series of 2D parabolic envelopes, and the second is of a hyperboloid of revolution. In between creating these two flip books, participants should make or observe an existing string art parabolic envelope and a 3D string art hyperboloid. Creating and experimenting with the flip books will enable participants to see how these curved surface can be created with only straight lines.