Marshall and I have built a car. It has two eyes that are green when it's going forward and when something is in front of it its eyes turn red and it turns 90 degrees then goes forward again. We used cardboard to build the base, chop sticks to support the wheels, duct tape, rubber bands for the wheels traction, 2 3d printed wheels and one plastic wheel. Next time I would make it better support for the wheels instead of chopsticks and duct tape. I would also add a top.