Prototyping

A typical prototype simulates or animates some but not all features of the intended system.
There are three categories of prototypes: Different types of prototypes involve different prototyping methods: For each method there are different appropriate tools: A complementary technique is the The Wizard of Oz method:
A human simulates the vertical functionality and provides the feedback for all user actions. This method is especially useful for prototypes of expert systems. IBM tried it with a prototype of a speech-recognition system. This method is difficult to implement and requires a very methodical human expert whose behaviour should be based on an algorithm.