IIRC in the late 80's it was said that a F1 car could create so much downforce that it could travel upside down.

This video shows something, something in very controlled conditions. It is impressive.

I am sure many here will have played Sonic the Hedgehog with it's looping and corkscrewing tracks. The latter would bring challenges.

Are we yet at the Men in Black tunnel congestion solution? And if we are, wow to how the road markings work.