Layering

Layering allows the designer to decide how much if any of a layer will be "connected" to any other layer. Designers are able to develop layers fairly autonomously, as their interactions are limited. For the user, the layering approach allows them to understand their environment in discrete units, and save any attempts at understanding the whole until all the units have been understood.

The separation of a project into layers allows the user to selectively determine with which layers to deal. Because the layers are generally connected only at key points (if at all), it is possible to approach one layer, decode it, then move onto the next layer. The key points in one layer serve as bridges into the next.