Prototyping styles

There are two basic styles of prototypes, each of which is used at different times in the development process. These are described as horizontal (big-picture) and vertical (drill-down).

Horizontal prototype

A horizontal prototype is targeting a high-level feature list for the app; for example, a mockup of the game interface and its screens (a wireframe) is considered a horizontal prototype. It has little or no functionality; it is much like a feature laundry list that identifies necessary elements for a particular aspect of the app. Context over content!

The following diagram represents a simple wireframe mockup of a game flow:

Vertical prototype

A vertical prototype is focused on a single aspect or set of aspects of the app. The goal is to explore and/or flesh out those elements to the point where it is clear whether they work or not. The emphasis is on functionality rather than presentation. Content over context!