There is some information about prototype

Prototyping is a method used by designers to acquire feedback from users about future designs. Prototypes are similar to mock-ups , but are usually not as low-fidelity as mock-ups and appear slightly later in the design process.

Prototypes may be horizontal or vertical: A horizontal prototype appears to have a very broad range of the intended future features, but only very little of the actual functionality of the features is implemented. For example, a horizontal prototype of a computer application may have a very well-developed and broad user interface (the horizontal dimension) but not much of the underlying functionality is implemented (the vertical dimension, i.e. the deeper layers of the software). Correspondingly, a vertical prototype only has very few features, which on the other hand are almost fully implemented or at least so-called "walking skeletons".