Half a century ago, Stern discussed this attribute of an artistic object and called it apparency. While art is not limited to this single end, he felt that one of its two basic functions was "to create images which by clarity and harmony of form fulfill the need for vividly comprehensible appearance." In his mind, this was an essential first step toward the expression of inner meaning.
The personal experience of most of us will testify to this persistence of an illusory image long after its inadequacy is conceptually realized. We stare into the jungle and see only the sunlight on the green leaves, but a warning noise tells us that an animal is hidden there. The observer then learns to interpret the scene by singling out "give-away" clues and by reweighting previous signals. The camouflaged animal may now be picked up by the reflection of its eyes. Finally by repeated experience the entire pattern of perception is changed, and the observer need no longer consciously search for give-aways, or add new data to an old framework. They have achieved an image which will operate successfully in the new situation, seeming natural and right. Quite suddenly the hidden animal appears among the leaves, "as plain as day."
Everything points to the conclusion that the phrase 'the language of art' is more than a loose metaphor, that even to describe the visible world in images we need a developed system of schemata.
An important feature of their strategy is parallel working - keeping design activity going at many levels simultaneously. The best cognitive aid for supporting and maintaining parallel design thinking is drawing. Drawing with the conventional tools of paper and pencil gives the flexibility to shift levels of detail instantaneously; allows partial, different views at different levels of detail to be developed side by side, or above and below and overlapping; keeps records of previous views, ideas and notes that can be accessed relatively quickly and inserted into the current frame of reference; permits and encourages the simultaneous, non-hierarchical participation of co-workers, using a common representation.
The drawing of partial solutions or representations also aids the designer’s thinking processes, and provides some ‘talk-back’. As well as drawing, innovative designers frequently like to undertake practical work related to the design solution, such as building models or mock-ups, or participating in construction.