Parallel development of different algorithmic strategies. Or, to wring a bit of the geek out and say it straight -- the two bots think different. Rocky, their red colored entry, tries to detect obstacles and then choose the best path to navigate around the obstacles to eventually get from point A to point B. Cliff, which is Virginia Tech's brown colored entry, instead plots a path from point A to B and swerves around the obstacles as they come up. So far Rocky, with it's obstacle based pathing, has seemed to have a better go at it. So much so that I would personally be surprised to see their Cliff entry make it to the main event. (update: Rocky made it to the finals, Cliff didn't.) (update to the update: Okay, so I was wrong. Both made it.)