An inventor has come up with a new design for a car that will drive on roads, sand, ice - and even water.    The all-terrain vehicle, which has a top speed of 62mph and works like a hovercraft, can move seamlessly between different surfaces.     Female designer Zhang Yuhan, 21, created the amazing machine - called the Volkswagen Aqua - for a competition sponsored by the German car manufacturer.     The vehicle's sleek sportscar-like design incorporates four high-powered fans and integrated airbags that inflate to lift it from the ground.  A large windscreen stretches above the front seats to give a panoramic view of the landscape ahead.    You enter and exit the car from a hatch at the rear of the car.