During the course of development of ideas from formalization to evaluation, it is important to make your intangible things tangible or give shape in the form of actual product to check feasibility and move on to the next stage of production. Typically, prototyping are done in order to validate the concept or idea and evaluate the design. Some people also call this a sample.
Prototyping is of paramount importance in design process and is practiced widely. Prototype development helps organization to have a room for further refinement and rectification in the concept if the prototype fails and this minimizes risk to the organization in terms of rejection of its products, waste of time, energy, and resources.