Given that F1 race cars can generate greater aerodynamic downforce at 200kph than their own weight, today’s invention is a Mobius strip-shaped racetrack.
It would be easy enough to create a track and support it on pillars, so that cars could pass each other side by side or belly-to-belly. See this to help visualise the event.
The start would have to be on a conventional, right-way-up section and the radii would have to be big enough everywhere to avoid braking to speeds less than 200kph (look out for that first corner).
Perhaps it’s therefore more a hybrid Nascar/F1 opportunity.