This wind-powered cart breaks the rules of science because it's actually faster than the wind itself. When the wind was only blowing at 20mph, the cart managed to hit speeds of 50mph. Here's how it works.
Of course, the cart, called DWFTTW, is ultra-lightweight and super aerodynamic. That's a given. But the science (or magic) lies in how its propeller and wheels interact: the 17 ft propeller is driven by the cart's wheels.
It's sort of confusing to think that the wheels turn the propeller, since the propeller also turns the wheels, but thanks to a very capable of transmission and the wind being an external power source, it manages to go faster than the wind.