Physical and Digital Shearing Layers

What can architecture teach us about digital design?

Carnegie Mellon University
Interaction Design Seminar, Professor Molly Wright Steenson
Fall 2019

Allen Hall: Thackeray Avenue and O’Hara Street in Oakland

Nested at the dead end of a small street in Oakland is a distinguished building called Allen Hall. Its six-story exterior is reminiscent of an ancient Greek temple. The structure is marked by four stone columns extending upwards that support a triangular roof. As I looked at this building, I felt a sense of reverence. Its exterior exudes ideals of democracy and civic duty. When I learned more about its history, I couldn’t help but feel that these values echoed its purpose.

Allen Hall’s history and values are apparent within its six layers of change — a concept developed by Stewart Brand in his book How Buildings Learn: What Happens After They’re Built.

All six layers work together to reveal Allen Hall’s distinguished history and its evolution. Although a digital product, the Google Chrome app can be considered similar to Allen Hall. The app is composed of digital layers that are also the result of a larger legacy and have evolved to the needs of its modern-day users.

Built-in 1913, Allen Hall was home to the Mellon Institute of Industrial Research. This institution was a large nonprofit dedicated to scientific research and education, with a central mission of benefiting society (Allen Hall, n.d.). Today, it is home to the University of Pittsburgh’s Department of Physics and Astronomy. The ideals of the scientific institutions housed within Allen Hall are very much reflected and embedded within the interior and exterior layers of the building.

Allen Hall’s Layers

Allen Hall was created in 1913 in a Greek Revival style. As a part of a larger acropolis-style plan, its dedicated purpose was to support scientific innovation (Allen Hall, n.d.). The Structure, Skin, Space Plan, Services, and Stuff all extend from this specific vision. It can be considered an institutional building because it was designed to “convey timeless reliability to everyone outside” (Brand 7). And it has maintained its reliability for advancing the sciences since its development. This is evident in the fact that its exterior has not been largely altered and that it still houses a department dedicated to science. Further, the history of this building is respected — so respected that two plaques detailing its famous inventions have been added to its exterior.

Signs honoring distinguished scientific past — Image 1: 1913 founders and commercial producers of Radium / Image 2: discoverer of Radium

But, most institutions are “high-change” environments (Brand 7). With major technological advancements since 1913, Allen Hall has had many upgrades. In 2012, the building underwent major retrofitting. This ensured that the building had the right Services to adapt to the needs of its modern-day occupants.

As I walked through the building, I could see this technological retrofitting throughout the building. This came in the form of security keypads, electric fire alarms, automatic doors, and sustainable water fountains. This upgrade ensures the longevity of the building and its usefulness to its tenants.

New technology embedded inside and outside the building

Also, its space is optimized for scientific experimentation, practice, and learning. The evolution of this is shown in the collection of old and new Stuff. The building houses old and new lab equipment, classrooms, desks, chairs, file cabinets, and offices.

Lab space & classroom space existing together

When thinking about layers and digital material, I wanted to look into a digital product that came from a similar type of legacy and one that has also evolved with its users. That’s when I thought about the Google Chrome App on my iPhone. It’s an app that is a result of a larger legacy.

Legacy Google Search on Web (1998) / Google Chrome on Mobile (2019)

The Chrome app is a child of Google’s web-based search engine. This search engine was invented in 1997 — back during the wild west days of the WWW. Today, Google has an entire ecosystem of products that connect back to its central mission of “organize[ing] the world’s information and mak[ing] it universally accessible and useful” (Our Mission, n.d.).

Even though the Chrome app lives in digital space, it has layers that contain traces of its history and evolution.

The Google Chrome App’s Layers

In the case of the Chrome App, the Site layer is complex and not static. The app is embedded in my iPhone (context 1), which is embedded within my environment (context infinity). I take this app from one context to another daily, hourly. Designing for the iPhone and for flexible contexts is fundamental in ensuring the app is useful for its users.

Ultimately, this app fits its purpose. The purpose of the Chrome app is to give users the ability to search more efficiently on their mobile device. Mobile devices are meant to be taken from context to context. Chrome is an extension of a legacy product that has been adapted to a new context.

Similar to Allen Hall, the Structure, Skin, Space Plan and Stuff all follow Google’s legacy. This time, this legacy has been adapted to a more mobile-specific design language. Search has been retrofitted for mobile. It’s supported by a backend technical system (Services) that is optimized around mobile devices searching the web. Further, wireframes and UI elements (buttons, micro-interactions) are created around ideas of quickness and tappability.

Two important differences between Allen Hall as physical material and Google Chrome as a digital material are the ideas of time and visibility. In digital space, time is still “the unit of analysis” (Brand 13), but it moves much faster. Change, especially of layers that are consumer-facing (e.g., UI), is more rapid. Further, users are less privy to all layers that might be more visible in physical space. Things like Structure and Services are usually kept secret to protect businesses. It’s only the architects of this experience — the designers, developers, product managers — that have full visibility.

Brand’s metaphors are useful when thinking about the evolution of physical and digital space. Products are created from a number of complex layers that work together. It’s important that the architects of these products create flexible material that can adapt to and evolve with end-users. Designers should maintain a strong process of creation that is embedded in strategy, forecasting, making, iterating, and testing. With a thoughtful approach, designers can create products with layers that honor the past and can evolve into the future.


Allen Hall. (n.d.). Retrieved from

Brand, S. (1994). How buildings learn: What happens after they’re built. New York, NY: Viking.

Our Mission (n.d.). Retrieved from

Interaction Designer | Carnegie Mellon University, School of Design | MDes ’21