The Design of Future Things by Don Norman Page A

A critical component here is the form by which the play is shown. A written description or a list of planned actions is not likely to be acceptable, requiring too much effort to process. For the playbook approach to be effective, especially for everyday people who do not wish to undergo training to accommodate the intelligent objects in their homes, a simple means of displaying the plays is essential.
    I’ve seen similar concepts at work on the displays of large commercial copiers, where the display clearly shows the “playbook”being followed: perhaps 50 copies, duplex, two-sided copying, stapled, and sorted. I have seen nice graphical depictions, with the image of a piece of paper turning over, showing printing on both sides and how the printed page is combined with other pages so that it is easy to tell if it has been aligned properly, with the page flipped along the short edge or the long one, and with a depiction of the final stapled documents stacked up neatly in a pile, with the height of the pile showing how far the job has progressed.
    When automation is operating relatively autonomously under loose-rein conditions, display schemes similar to the playbook are especially relevant to allow people to determine just what strategy the machine is following and how far along it is in its actions.
The Bicycles of Delft
    Delft is a charming small town near the Atlantic coast of the Netherlands, home of the Technische Universiteit Delft, or in English, the Delft University of Technology. The streets are narrow, with several major canals encircling the business district. The walk from the hotel section to the university is picturesque, meandering past and over canals, through the narrow winding streets. The danger comes not from automobiles but from the swarms of bicycles, weaving their way at great speeds in all directions and, to my eyes, appearing out of nowhere. In Holland, bicycles have their own roadways, separate from the roads and pedestrian paths. But not in the central square of Delft. There, bicyclists and pedestrians mix.

    F IGURE 3.3
    Holland is the land of multiple bicycles, which, although environmentally friendly, present a traffic hazard to people trying to walk across the square. The rule is: Be predictable. Don’t try to help the bicyclists. If you stop or swerve, they will run into you.
    (Photograph by the author.)
    â€œIt’s perfectly safe,” my hosts kept reassuring me, “as long as you don’t try to help out. Don’t try to avoid the bikes. Don’t stop or swerve. Be predictable.” In other words, maintain a steady pace and a steady direction. The bicyclists have carefully calculated their course so as to miss one another and all the pedestrians under the assumption of predictability. If pedestrians try to outmaneuver the bicyclists, the results will be disastrous.
    The bicyclists of Delft provide a model for how we might interact with intelligent machines. After all, here we have a person, the walker, interacting with an intelligent machine, a bicycle. In this case, the machine is actually the couplet of bicycle+person, with the person providing both the motive powerand the intelligence. Both the person walking and the bicycle+person have the full power of the human mind controlling them; yet, these two cannot coordinate successfully. The combination bicycle+person doesn’t lack intelligence: it lacks communication. There are many bicycles, each traveling quite a bit faster than the pace of the walker. It isn’t possible to talk to the bicyclists because, by the time they are close enough for conversation, it is too late to negotiate. In the absence of effective communication, the way to interact is for the person walking to be predictable so that no coordination is required: only one of the participants, the bicycle+person has to do planning; only one has to act.
    This story provides a good lesson for design. If a person cannot coordinate activities