The Concept Cars Raising Eyebrows at the 2015 Frankfurt Motor Show

A motorshow wouldn't be quite the same without a flurry of concept cars. Although such vehicles are rarely made available for purchase, they serve many purposes; not least to generate excitement about a brand, convince the market that a company is still capable of innovation, or to work as design studies for future road cars.

The S-Class-sized IAA takes its initials from the Frankfurt Motor Show's official name, Internationale Automobil-Ausstellung, but actually stands for Intelligent Aerodynamic Automobile. It's a valid name, as this four-seater luxury sedan physically transforms itself to increase efficiency. Below 50mph, it looks like a sensible enough imagining of a Mercedes CLS from the 22nd century. But drive any faster and it begins to change shape.