I found this interesting quote over at A List Apart, a brilliant web design resource:
Design is largely an exercise in creating or suggesting contrasts, which are used to define hierarchy, manipulate certain widely understood relationships, and exploit context to enhance or redefine those relationships…all in an effort to convey meaning.
Isn’t this what we do with teaching? Use contrast to try and make a point, or to illustrate the difference between one concept and another? Is this what we are doing when we design instruction?