wintersynth brings us a story about a group of enthusiasts who made a catapult out of a 2,800lb industrial robot arm. They used it to launch bowling balls, fireballs, and cans of beer toward a stationary target, and they controlled the catapult's aim with a graphical UI on a laptop. "I wanted to be able to control the rotation of the robot so we could aim the robot from the laptop, but I quickly realized that since the desert is so flat, we could do some basic ranging on the target too. I also wanted the targeting to be overlaid in 3d over a photograph of the target area. The software needed to control the robot like an MMO or RTS game. I suspect that video games, in general, have some of the most optimal control interfaces. I wanted to try a control scheme similar to the area effect spell targeting in World of Warcraft."