The Lego Mindstorms Robot Command eXplorer (RCX) is a popular robotics kit that provides an immediate "out-of-the-box" opportunity to explore software controlled robot interaction. The limitations of the RCX provide a direct challenge that is typical of real-world embedded system development. This paper describes the Java-based development of a set of robots that coordinate to play the game of tic-tac-toe. Three key challenges were investigated in the project: 1) recognition of the state of the

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... game board, 2) computation of the next-move within a reasonable timeframe using robots working in parallel, and 3) navigating a robot to the proper board location to mark the desired move. Game board analysis takes the form of a robot that performs optical scanning. A min-max tree algorithm was implemented in the primary control robot to determine the next best move. Various robot components were implemented to affect the physical movement of the robots and to mark the appropriate tictac-toe cell. The inefficiency of the min-max algorithm provides an opportunity to explore the use of parallelism among the robots to compute the next best move at specific levels of game play. In addition to the research results, the project informs the appropriateness of using the RCX as the basis for introductory programming classes and to provide a platform to drive undergraduate research.