"Viewpoint: Toward a computer for Visual Thinkers" : Scott Kim, 1988. "What would a visual programming language look like, if computers had been invented by artists and visually oriented people, instead of by mathematicians and engineers?" As a first step, Kim proposes that the user's mental model of the program should be perfectly aligned with what is shown on the display: no hidden state. http://www.scottkim.com.previewc40.carrierzone.com/viewpoint/index.htmlThe following video shows a graphical/textual editing environment where the full state of the editor is shown on the display. To use the editor, you must think visually, about what is shown on the display, instead of thinking abstractly and symbolically about the system's hidden state.