Computational thinking and mental models: From kodu to calypso

Reasoning about programs is an important component of computational thinking. Laws of computation give meaning to the formalisms in which programs are expressed, and can be used to predict or explain program behavior, or to uncover bugs. This paper presents Calypso, a language inspired by Microsoft's Kodu Game Lab but designed for programming actual mobile robots rather than characters in a virtual world. The initial implementation of Calypso uses the Cozmo robot by Anki. Like Kodu, the Calypso interpreter can be described by five key laws. An understanding of the laws and how to apply them constitutes a mental model of computation. Calypso provides a variety of affordances and scaffolding techniques to foster development of effective mental models and facilitate computational thinking.