The Psychology of Invention in the Mathematics

User interface is primarily an act of theatrical design. The thing is about vision, same with the ear. You can only see a few at a time in detail, but you can be aware of a hundred things at once. This is why no experience programmes have big, multiple screens. They're working on something where the result is going to fit on one screen, but you have to have all other stuff. It's like when you make an arch it's not just piling up the bricks. You have to put this whole scaffolding up until you get the keystone in place.