The most aerodynamic shape is the teardrop, which is formed by the flow of water down an object meeting opposition from the air around it. The teardrop shape has a rounded nose at the front that tapers towards the rear, and it is the last of three shapes (sphere, flat disc, and teardrop) to stop moving when sent at the same speed, due to its ability to stay attached to the airflow longer than the other shapes. The teardrop shape has a drag coefficient (Cd) of 0.04, which is the most aerodynamic shape in nature. Many aerodynamically efficient cars often feature a teardrop shape, such as the Porsche Taycan and the Mercedes A-Class Saloon.