The LEGO Programmable Brick gives children the ability to create physical artifacts, such as vehicles and robots, and program them with interesting behaviors. However, programming is difficult to learn, even for adults. Children often lose interest in further exploration of programming through adult learning mechanisms. Environments that support a gradual transition from manual control of the physical artifact to complete programming substantially simplify the process of programming. The combination of LEGOsheets and the Programmable Brick is an educational environment that provides a gentle, enticing introduction to programming and the design of mechanical artifacts. This paper introduces LEGOsheets, a rule-based programming environment that allows children to simulate and manipulate the LEGO Programmable Brick.