Abstract
We have developed a picture language system for constructing 3D models in Scheme, one version of Lisp. Understanding both procedural abstractions and data abstractions is important for all people who learn to write efficient and compact source codes. A picture language has been the most effective way to understand those concepts, because it can present structures of programs as intuitively and visually understandable 2D figures, which was originally introduced in a legendary book of computer science, SICP (Structure and Interpretation of Computer Programs). We designed and implemented the extended picture language for 3D models using JAKLD and enabled the system to export models in 3D printable format, in order to deepen learners' understanding of abstractions by analogy of spatial fractal structures of substantial models. We report the use of our system as a teaching material in a lecture for first-year undergraduate students.
