Imagine you decide to build a house. Even if this is just a dog kennel, you won't get to work until you draw a plan. Modeling the interfaces of a future resource is similar to a project in construction: a prototype helps the client and developers understand how the elements will be located, how they will interact with each other. Design is not a waste of resources; it is risk prevention. The prototype helps to formulate ideas about the result, optimize time, plan costs and insure against an unscrupulous partner.