Chap ter 7 Reduction FIGURE 7.1 LuCa's big adventure with a do-it-yourseLf sCaLe I'm in the neighborhood supermarket for my weekly shopping expedition. My cart is loaded with fruits and vegetables, and I approach one of the many do-it-yourself electronic scales to weigh the different parcels and get their costs in order before lining up. As usual, when I get to the scale I already forgot the codes associated with some of the things I'm buying so I have to go back to the stands and look up their numbers again. The system works by associating any fresh fruits or vegetables with a specific number: you then have to choose that number or punch it in on the scale. This association, however, is not stable, as it changes with the normal turn- over of fresh produce. In the winter, a certain number might be oranges and in the summer peaches or watermelons. The scale has a large touch-screen with buttons: even when each button presents an icon beside the number, their Pervasive Information Architecture © 2011 Elsevier, Inc. All rights reserved. 143