Design is interactive through artifacts. Artifacts are paper representations, models, computer simulations and objects. The process of design is based on people interacting with artifacts and with each other through artifacts, to develop the best product possible to meet the criteria. Design is iterative. That means that a model is developed, tested, and assessed over and over again, for success or failure of a product, related to certain key criteria that have been established in advance.
Failure is as informative, often more so, than success.
The process of design cycles through with refinements and improvements until designers are as satisfied as they can be that the product designed on paper or in models or simulations will meet the criteria when it is actually manufactured and in operation. Design is reflective and collaborative, and designers use reflection and collaboration to help them justify why they are doing something and why they believe it will be successful. In process talk students tell why they think something will work. Design depends on representations as tools for thought and problem solving. Drawings, sketches, and models, with labels and measurements and specifications for materials are key.