When I conceptualize a sandwich, I generally think of it the same way that I perceive it, combined with memory of the flavors, textures, and emotional connotations. However, when I design a sandwich, I approach the problem from the inside out.
What is the feature of the sandwich? Roast beef. The point of this whole sandwich is that it is a roast beef delivery system. Now that I have decided on the feature with the most value, I can approach the rest of the design challenge as one of finding the best complements to the feature.
Cheese? Swiss. Roast beef and swiss just sounds right.
Veggies? Of course! Tomatoes, lettuce, some bell peppers, and for salty complement, a pickle on the side.
Condiments... horseradish sauce. Mmmm.
What's the best way to wrap this up? The bread is a key component, but it is a servant to the rest of the sandwich experience. Sure, sometimes the bread is the feature, like when my wife makes peanut butter and banana sandwiches on graham bread, but not this time.
Regardless of whether I was ordering this sandwich or building it myself, I would have to consider these ingredients in a different order. As a sandwich builder, I need to select my bread first, then spread the condiments, then stack up the fillings.
When you go to The Atrium at BSU and go to the deli sandwich counter, they have a touchscreen display for selecting what you want. It's screen-oriented, with the first (pertinent) screen showing breads, then meats, cheeses, vegetables, and condiments.
This sequence of screens is builder-centric. The order of selection is exactly the order that the staff behind the counter will use to build the sandwich. From each screen, you cannot see the options on the other screens, because they are not pertinent to the assembly-line approach to creating the sandwich.
The touch screen interface is less user-friendly than the paper-based system that preceded it. Previously, any number of clients could grab a sheet, check the meats, cheeses, breads, etc. that they want, put it in the bin, and wait for the sandwich. Now, you have to wait in line behind the single touchscreen station. I find that this pressure adds to my frustration, but I usually approach the counter without knowing what I want. That is, I use the sandwich design experience to explore both the design space and my own desires.
Also, they forgot my horseradish sauce.