This paper presents a new algorithm, Hit-or-Jump, for embedded testing of components of communication systems that can be modeled by communicating extended finite state machines. It constructs test sequences efficiently with a high fault coverage. It does not have state space explosion, as is often encountered in exhaustive search, and it quickly covers the system components under test without being "trapped", as is experienced by random walks. Furthermore, it is a generalization and unification of both exhaustive search and random walks; both are special cases of Hit-or-Jump. The algorithm has been implemented and applied to embedded testing of telephone services in an Intelligent Network (IN) architecture, including the Basic Call Service and five supplementary services.

We survey the literature about the teaching and learning of recursive programming. After a short history of the advent of recursion in programming languages and its adoption by programmers, we present curricular approaches to recursion, including a review of textbooks and some programming methodology, as well as the functional and imperative paradigms and the distinction between control flow vs. data flow. We follow the researchers in stating the problem with base cases, noting the similarity with induction in mathematics, making concrete analogies for recursion, using games, visualizations, animations, multimedia environments, intelligent tutoring systems and visual programming. We cover the usage in schools of the Logo programming language and the associated theoretical didactics, including a brief overview of the constructivist and constructionist theories of learning; we also sketch the learners' mental models which have been identified so far, and non-classical remedial strategies, such as kinesthesis and syntonicity. We append an extensive and carefully collated bibliography, which we hope will facilitate new research.

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