Now that the AP Computer Science exam is over and we’ve finished our capstones (more on those later), we finish the year building LEGO MINDSTORM NXT robots and programming them in Java using leJOS. This is a perfect project for the end of the year because it is extremely engaging, leverages everything we’ve studied this year, and adds a new element of the interaction between software and the real world. Last year, the students built sumo bots and competed against each other. Based on reflection and what I learned at last summer’s Tapestry Workshop, this year’s challenge is less directly competitive. Students have to design, build, and program a robot to push six peanut butter jars out of a circle without having the robot leave the circle. Underclasses, who are in school after the seniors graduate, have the additional challenge of having their robot placed in a “house” (a box with an open side) in the center of the circle from which they must first escape.