Audi Cetus is a hydrogen-powered, zero- emission city car, designed to change everyday city travel. The idea was to create a car for 2 people that will be likeable and fun, in an effort to restore excitement to the experience of driving. A playful conceptual exercise, truly embraces aerodynamics to both reduce energy consumption and form part of a future design aesthetic. The smooth curves and streamlined shell mimics the movement of a swimming fish, in an effort to correlate the similarities of the hydrodynamic properties of marine creatures with the aerodynamic performance of the car. This results to an energetic and distinctive form that is formulated by the little details such as the flow of the exterior shell. The dynamics of the streamlined silhouette are further emphasized by the natural smooth form that flows to give the car a distinctive appearance. By incorporating this concept the design becomes a more visual expression of the smooth flow of air and this underlying order gives the car its character.