 Computer modeling is now being extensively used in automotive design, both for form (in the styling and aerodynamics of the vehicle) and in function—especially for improving vehicle crashworthiness and in weight reduction to improve mileage.The most common use of the word prototype is a functional, although experimental, version of a non-military machine (e.g., automobiles, domestic appliances, consumer electronics) whose designers would like to have built by mass production means, as opposed to a mockup, which is an inert representation of a machine's appearance, often made of some non-durable substance.An electronics designer often builds the first prototype from breadboard or stripboard or perfboard, typically using "DIP" packages.