Visual Programming in a Visual Domain: A Case Study of Cognitive Dimensions Francesmary Modugno* T.R.G. Green** Brad A.~Myers* *Carnegie Mellon University **MRC Applied Psychology Unit 5000 Forbes Ave 15 Chaucer Road Pittsburgh, PA 15213 Cambridge CB2 2EF, UK {fmm,bam}@cs.cmu.edu thomas.green@mrc-apu.cam.ac.uk Abstract We present a new visual programming language and environment that serves as a form of feedback and representation in a Programming by Demonstration system. The language differs from existing visual languages because it explicitly represents data objects and implicitly represents operations by changes in data objects. The system was designed to provide non-programmers with programming support for common, repetitive tasks and incorporates some principles of cognition to assist these users in learning to use it. With this in mind, we analyzed the language and its editor along cognitive dimensions. The assessment provided insight into both strengths and weaknesses of the system, prompting a number of design changes. This demonstrates how useful such an analysis can be. KEYWORDS: Cognitive Dimensions, End-User Programming, Programming by Demonstration, Visual Language, Visual Shell, Pursuit.