Mine go further (230+) but I got a weird duncecap-like structure over the rear wheel that keeps cropping up, putting the center of gravity too far back and maki

Mine go further (230+) but I got a weird duncecap-like structure over the rear wheel that keeps cropping up, putting the center of gravity too far back and making them fall over backwards. Interestingly, instead of getting rid of the balance problem, my cars are evolving a wheely bar to prevent the backward flip at the expense of speed. I wish the goal involved speed in combination with distance. Update: stagnation after generation 10. I spun up another instance and it is amazing how different that one is evolving.