rope climber - I designed and built the rope climber to race 3 stories up a 1/4" steel cable tensioned to the floor. Using 2 motors, each with one pinion gear and one large gear, driving the wheels. Using springs to tension the wheels to the cable. I also used four 9 volts batteries in a mix between series and parallel set up for maximum power. The design also had to be balanced and couldn't tilt while it was climbing. I received 2nd place.