Sublime

though there was no compelling need to do so.

and focus resources in an efficient manner.

In both cases, the high degree of convergence indicates a stable environment—one that has not changed much over time—and designs that closely approximate the optimal strategies afforded by that environment. The

As the flexibility of a system increases, the usability of the system decreases.

Perceptibility is achieved when everyone can perceive the design, regardless of sensory abilities.

When time and resources are limited, resist efforts to correct and optimize designs beyond the critical 20 percent, as such efforts yield diminishing returns. Generally,

and mental models of how people interact with systems (interaction models).

Given a choice between functionally equivalent designs, the simplest design should be selected.1