The user can read this book and understand the concepts from the photographs of 3D printable models alone. However, since many models are puzzle-like, we encourage the reader to print the models on any consumer-grade filament based 3D printer. The models are available for download in a freely-available open source repository. They were created in the free program OpenSCAD, and can be 3D printed or modified by the student in OpenSCAD to learn a little coding along the way.