Mobility planner, Aarhus, Denmark
Ole B. Jensen
Professor of Urban Theory, Department of Architecture, Design and Media Technology, Aalborg University, Denmark
Reference this essay: Wind, Simon and Ole B. Jensen. “Feedback Urbanism at Play: Formation of Publics through Playful Friction in Urban Interfaces.” In Urban Interfaces: Media, Art and Performance in Public Spaces, edited by Verhoeff, Nanna, Sigrid Merx, and Michiel de Lange. Leonardo Electronic Almanac 22, no. 4 (March 15, 2019).
Published Online: March 15, 2019
Published in Print: edit
The neo-liberal smart city bandwagon (spearheaded by IBM, Cisco, Google etc.) mainly advances the upsides of using technologies and data to make cities more efficient, competitive, sustainable, and ultimately, as they claim, livable. However, critics point out that achieving livable and attractive cities also depends on framing conditions for softer aspects such as social interaction and the formation of publics and local communities. In this paper, we propose the term Feedback Urbanism as an alternative perspective, one that highlights the (smart) city as hybrid assemblages of exchanges, circulations, and effects. Thus, we aim at a more literal understanding of what interactions and effects occur when technologies come into contact with citizens in the urban environment. To study this in detail, we focus on the Urban Interfaces of technologies, people, and places and their combined effects in two interactive installations in Denmark. We show how they augment and challenge experiences, meanings and the use of urban space and facilitate social interaction through playfulness. Finally, we discuss how small-scale interactive urban installations might provide new typologies for creating sensorial experiences and platforms for citizens to become involved in negotiating their everyday places and practices in playful ways.
Keywords: Feedback urbanism, Smart City, play, interactive installations, publics
Contemporary technological achievements divide societies (as they so often have done in the history of technology) as much as they enable new forms of associations. In this paper we seek to offer a critical re-reading and re-framing of so-called ‘smart city’ technologies. In doing so, we move away from the corporate salutes as well as from the generic and globally applicable theories and concepts. We argue that what is missing is a framework that seeks out a descriptive and literal understanding of the features of the technologies (i.e. by asking questions like: What do they do? How do they work in real life situations?) and, at the same time, acknowledges the need for a critical and people-oriented approach to these technologies (i.e. by asking questions like: What human-human interactions do they afford? Which communities may form around these technologies?). In order to step back from the normative and contested engagement of ‘smart’ and explore how these technologies perform, we propose to consider the notion of ‘feedback.’ As we are looking at communication and digital technologies and their relational coupling between sensors, actuators, artefacts, people and places, we claim that feedback is a better term for describing and highlighting the complex exchanges, circulations and effects that occur. To understand how feedback takes place in these systems, we direct our attention towards the important point of interaction and interchange – to the specific ‘interfaces’ – between the elements in the system. We may think of these interfaces as ‘critical points of contact,’ where one system (critically) interacts, affects and informs another.  Studying the ‘interfacing’ between systems, technologies and humans also enables a focus on the actual, concrete and specific situations rather than a generic and global system.
Consequently, in highlighting the interface we refute any discrete understanding and instead insist on contextualizing the interface in its human and material setting. As urbanists, we find this particularly pertinent as it is often insufficiently developed in the generally techno-optimist smart city discourse. It makes a difference that the technologies we study are emplaced in cities and that they are explored, used and perceived in urban settings. The ‘cityness’ of (smart) cities, or the urbanism of the material context of these technologies, suggests questions related to human communities, as well as to the many different rationalities of engagement. Often the ‘smart city’ literature is articulated in the language of instrumental rationality and rational agency, focusing primarily on improving cities through increased efficiency, safety and economic growth. As these aspects of the smart city are thoroughly described in literature, we engage with the playful dimension and efficiency in this paper. The engagement with new technologies physically situated in the urban environment may take on playful properties that we need to account for when we see them empirically. Even more important, however, the creative and playful framing enables us to address how new technologies might support and even catalyze ‘softer’ and more elusive issues such as social interaction, cohesion and formation of publics that are just as important in achieving livable and attractive cities. Hence, we aim to contribute to a fuller understanding of contemporary urban potentials and applications of digital and networked communication technologies.
From this theoretical starting point of feedback and interface, we make three overall analytical gestures that contribute to the general discussions of smart cities. First, thinking through the flat ontology of ‘assemblage,’ we seek to shift the focus away from technologies and instead examine the critical and hybrid relations and interfaces of technologies, people and places. Second, much of the smart city discourse and discussions focuses on large-scale – and often ‘hidden’ – technical and multi-scalar systems and/or processes with little direct relevance and meaning for actual citizens. By using the term ‘urbanism,’ we wish to draw attention to the dimensions of the smart city that deal with the physical and lived environment. If the smart city is ultimately about creating good and livable places, then a stronger focus on the actual situated and socio-material interfaces in people’s everyday lives is needed. Third, with this discrete focus on the particular situation and physical environment, we attempt to ‘scale down’ and sharpen our analytical sensitivity to examine how technologies are changing, enhancing and augmenting ongoing formation processes of public urban space through situated and social performances and practices.
With a point of departure in feedback urbanism and the notion of urban interface, we aim to provide an analytical infrastructure that is able to ground and critically scrutinize the emerging technologies-cities nexus we find in the smart city. We think of these two concepts as ‘tools’ that allow us to analytically operate differently. We propose that feedback urbanism and urban interface as theoretical lenses that hold key differences, which allow them to complement each other in analyzing how hybrid gatherings of technologies, places and people are fast becoming reality and radically change how we perceive, think about, and use cities and places in everyday life. In particular, feedback urbanism advances the circulatory motion of technologies, data, materialities and people that form ‘place assemblages,’ whereas urban interface allows us to zoom into these feedback assemblages and focus on the relations and intersections between these hybrid bodies and their dynamic structuring of social practices and interactions with the environment.
Using this combined framework of feedback urbanism and urban interfaces, we unfold two small scale cases of hybrid urban interfaces of technologies, people, and places in Denmark. The first case is a permanent media surface called DIA, which is integrated on the façade of the Confederation of Danish Industry’s HQ building in the center of Copenhagen. The second case is a temporary vibrotactile and vibroacoustic urban installation called The Humming Wall, which was placed in a public park in Aalborg in 2014. Through the two cases we examine and compare how urban interfacings augment and challenge experiences, temporalities, meanings and use at these two sites through hybrid feedback loops of materialities, humans and technologies. Even though both Aalborg and Copenhagen invest in articulating and promoting themselves as part of the smart city movement, none of the projects reviewed in the paper were born or communicated as smart city projects as such. Instead, they are simply promoted as experiments and playful installations that are meant to explore the interfacings of technologies and humans. Finally, we discuss how technologies in small scale urban interventions and installations might point to new typologies, tools and infrastructures, not only for professional urban operators (i.e. urban designers, architects and planners) to create new experiences, actions spaces and public spaces, but also for citizens to become more actively involved in the ongoing negotiations and formations of their everyday places and practices in novel and playful ways.
Approaching Smart City through Feedback Urbanism and Urban Interfaces
Since the turn of the century the term ‘smart city’ has become increasingly popular as a catch-all concept designating the nexus of technologies and data in future cities and societies.  The term has become massively contested, as it is used and defined differently in various fields and disciplines, and carries multiple connotations (see Albino et al. 2015 for an elaboration). Global technology conglomerates, such as IBM, Cisco, HP etc., promote a ‘corporate’ version of the smart city, where new technologies, networked systems, massive computing power and unprecedented data generation allow for the control and management of the city with all its processes and complexity. Besides increased efficiency and saving city budgets, this vision of the smart city promises to deliver effective tools and solutions for dealing with the pressing environmental, social and economic challenges that our increasingly urbanized societies face. In addition, the major smart city solution providers have recently, with a newly found focus on the ‘smart citizen,’ also included the creation of more livable and democratic cities to the multiple benefits of their holistic smart city solutions.
Alongside these positive statements, there is however a growing critique of the corporate and neoliberal smart city.  A key tenet of this critique aims at the one-sided, large-scale and top-down focus on optimization, security and economic growth. This promotes a simplified and reductive view of the city’s complexities that neglects to recognize and support what Saskia Sassen has called the “incompleteness of cities,”  the kind of openness that leaves cities to be negotiated, remade and developed. The corporate smart cities fully strapped with smart infrastructure and technologies such as Masdar City, New Songdo and PlanIT Valley hardly convince critics that these places are actual good and livable cities for their inhabitants. Moreover, much criticism is waged against the hidden normativity and the underlying mainstreaming of what the good (city) life is.  The corporate smart city is far from a-political and neutral, although it is often marketed as such, but is instead, as Michiel de Lange finds, driven by “logics of consumption, control and capsularization [that] do not empower citizens to become active players in their cities.”  What seems to stand out is that the term ‘smart city’ has become a ‘travelling idea’  as it travels the globe in the minds and hands of urban developers and city builders.
We acknowledge that there is a certain cybernetic ring to the notion of feedback. The functional feedback loops of information gathering and data circulation have cybernetic dimensions, but we propose thinking of them in a more descriptive manner. Compared to ‘smart’ we argue that ‘feedback’ is less normatively loaded and connotes a more descriptive concept. Elsewhere we have argued that:
The key feature from the smart city literature is (when it comes to technology) the capacity to harvest, store, analyze, and distribute very large amounts of real-time data in complex systems of variable accessibility. The term “feedback urbanism” will be used here as a shorthand for this predominant feature and complex dynamic. 
Part of the feedback urbanism agenda is an attempt to re-articulate the relationship between cities and networked technologies in order to overcome some problematic uses of smart city terminology. In parallel, and slightly overlapping with the smart city discourse critique of Maarten Hajer and Ton Dassen,  we see at least five reasons to come up with alternatives to the smart city concept. These all involve countering simplistic or problematic notions connected to the smart city conception like an overly simplistic society–technology dichotomy; an overly optimistic promise or the opposite, a pessimistic dystopia; an easy technical fix to the large urban challenges we face; or simply a mere ‘virtual’ or digital phenomenon. Therefore, we propose a more descriptive, pragmatic, and networked concept, taking into account the ‘symmetric’ relation between technology, sociality, humans, and the built environment.
We attempt to find a balance between the uncritical appraisal of the smart city notion, on one hand, and the ideological standard critique on the other. In our pursuit of a middle ground, we propose the notion of feedback urbanism as a pragmatic yet critical lens on this emerging technologies-cities nexus in which the smart city is situated. While critical, we wish to emphasize that this is an open-minded and explorative inquiry of the potentials and pitfalls of emerging technologies. It is also important to note that we make use of the term feedback quite literally. The emerging technologies of our interests (i.e. sensors, tracking devices, mediated surfaces, dynamic lighting, haptic actuators, etc.) hold the capacity to ‘sense,’ collect, manipulate, order, operate, and circulate data and information in loops that have feedback as their defining character. In other words, smart city technologies work through complex networks and assemblages where they provide the collected data as a ‘field of actions’ in which agents, institutions, humans, and technologies may operate. In these assemblages, data and information is generated, assessed, manipulated and ‘fed back’ to the particular situation creating new fields of action. Moreover, this ‘loop movement’ might further be aggregated into complex and multi-scalar systems of humans, artefacts, technologies and places that afford even more complex situated actions, experiences and meanings as a function of the information and data being re-circulated to the various agents.
As we wish to analytically approach the two interactive installations presented above as urban interfaces, we first lay out some theoretical infrastructure to provide a starting point for diving into an analysis of The Humming Wall and DIA installations and discuss their latent generative effects in more detail.
Reviewing the literature, we find that the notion of interface holds several meanings. The Merriam-Webster dictionary describes an interface as “a surface forming a common boundary of two bodies, spaces, or phases,” or “the place at which independent and often unrelated systems meet and act on or communicate with each other.”  In the world of media technologies, this might point to any medium such as the touch screen, keyboard, operating system, etc. that allows a subject to interact with a system.  In contrast to this ‘object-focused’ understanding, we might think along the same lines as Branden Hookway, who defines interface as the “relation with technology rather than as a technology in itself.”  A parallel can be drawn to Ole B. Jensen and Nicola Morelli’s notion of ‘Critical Point of Contact’ (or CPC), which they define as:
[…] nodes that connect and work as meeting points between systems that make a difference. Some points of contacts are more interesting than others and this is what makes them ‘critical’ […]. CPCs are sites of difference. They become critical when the one system changes/influences the conditions of the other as where entities, flows and qualities are modified as a consequence of the CPC (e.g. as when I become a passenger by a function of the CPC of the metro station and my economic resources and other capabilities to embark). 
These are critical because of the interrelationship between elements in the system or assemblage, not just because they come into contact with each other but because they actively affect and change each other. As Galloway also emphasizes, this means that interfaces should not be considered objects but rather “autonomous zones of activity” or “processes that effect a result of whatever kind.”  Following this, we might understand interfaces as simply a kind of “agitation” or “generative friction.”  In discussing these various meanings, Nanna Verhoeff provides a clearer distinction as she speaks of “interface” as a noun, pointing to its material manifestation on the one hand and the more abstract “interface-ing” as a verb on the other, emphasizing the dynamic relational process that takes place between different entities interacting.  This distinction allows us analytically to shift attention from “media (fixed) objects to (on-going) practices of mediation” within feedback assemblages.  In the following analysis we lean towards the latter and inquire into what Verhoeff denotes as a “performative conception of the interface.”  This means that besides the descriptions given above, we will not touch more upon the objects and materiality of the installations, but instead focus on what the two installations in question do and how they catalyze, structure, and potentially transform situated interactions, practices and meanings.
It is outside the scope of this paper to define the ‘cityness of urbanism’ as the very context of these different forms of media and communication technologies. We propose that inquiring into and understanding new technologies situated in cities cannot take place without considering the urban environment. Since we consider architecture and urban design as one of the cornerstones of the feedback urbanist perspective, we must touch upon the urban dimension. There are two immediate aspects that need to be brought into the discussion. One is the material aspect, which relates to the fact that smart cities are material, physical and spatial sites and not only ephemeral and unearthly digitized realms.  Second, we bring to the table the insight from many classic urbanist analyses, namely that the city is as messy, disorganized, frightful, chaotic, and playful as it is ordered, rational, and organized.  The playful dimension of general city life has been further addressed in the emerging literature on cities, digital media and games. 
Part of the DNA of cities is the juxtaposition of difference and playful engagements with spaces and ‘others.’ Indeed, the livability of cities and attractiveness of places are also functions of the unforeseen and ludic character of the material environment. From Charles Montgomery’s call for the ‘happy city’  to Bjarke Ingels’ notion of ‘hedonistic sustainability’  there is renewed attention for the fragile but essential dimensions of urbanism that have to do with human flourishing and playful exchange as much as with such ‘serious issues’ as growth, policies, and control. This, however, tends to be forgotten in rational systems of digital information gathering and circulation. The inclusion of play and the ludic in the framing of feedback urbanism also speak vividly to the cases we entertain in the next section of this paper. Rather than having chosen ‘serious’ technological interventions that might provide real-time travel data or lower energy consumption, we deliberately have chosen projects that open a conversation about the new technologies’ playful potentials in the urban environment. We seek out projects with a capacity to foster social interaction and bring publics together in the fleeting and ‘mobile agoras’ of the city. 
From this conceptual framing we now turn to two examples of interventions in the city that usefully illustrate the applicability of feedback urbanism.
Analyzing The Humming Wall and DIA
The two projects we chose as cases for this paper exemplify hybrid ‘feedback loops’ as assemblages of people and media technologies situated in public urban spaces. In investigating these installations, we seek to empirically ‘ground’ and catalyze a discussion on how media technologies might augment and enhance spatial and aesthetic sensorial experiences as well as engender social interactions and temporary publics amongst citizens.
The first project is an interactive urban environment called The Humming Wall, which was part of a temporary research art installation created by researchers at Aalborg University in Denmark.  The installation was located in a park in Aalborg’s city center and harbor front for five weeks during the summer of 2014. The installation was approximately 12 m wide, 3.5 m deep and 2.7 m high and was shaped to fit the location, that is, blend in with the curvy paths in the park, and provide seating as well as shelter people against the strong western wind that blows along the harbor front. The installation explored how vibrotactile-vibroacoustic interactive technology integrated in a public urban environment could encourage extended recreational use of the area and facilitate social interaction.  People could activate the installation with several touch gestures (knocking, tapping, and swiping) and generate a feedback effect through haptic vibrations, low frequency humming sounds and DMX controlled warm and cold lights. 
The overarching concept was to create an artefact that was immediately responsive to several users at the same time (multi-touch) so that they could potentially create a collective ‘music’ experience through which they could ‘hear-feel’ each other. The feedback hum emitted from the wall was specifically designed to hit a low but audible frequency (40-50 Hz) to attract new users, and create a calming sensation for users touching, sitting or lying on the wall surface.  In their own evaluation and study of the effects of The Humming Wall, the team documented that it had this effect on the users. 
As an art project developed at Aalborg University for the purpose of research, The Humming Wall was not born as a smart city initiative. The city of Aalborg has a smart city initiative, but their focus is primarily directed towards business development and optimization of existing processes and systems, for example, creating more efficient and sustainable infrastructure and energy networks. The municipal approach to the smart city initiative is top down and focuses on how technologies might empower and optimize the city’s urban system. Thus, as a small-scale experimental art installation, The Humming Wall was something entirely different. However, the project should not be understood as a critique of the ‘corporate’ approach to the smart city but rather indifferent to the debates of the smart city and more concerned with exploring the interface of technology and human interaction.
The second project is a media façade of the Confederation of Danish Industry’s (DI) headquarter building in the city center of Copenhagen (located in the heart of the city at Rådshuspladsen). This installation, designed by the Danish architecture firm Kollision in 2013, encapsulates the building with 80.000 LED lights organized in a diagonal pattern.  The light installation can be fully controlled through an app and programmed to change from a dynamic light display to an interactive light experience with which citizens can engage.  The installation ‘speaks’ to the light architecture of the other buildings surrounding Rådshuspladsen (many of which have older neon light billboards). This particular place is iconic and well known in Denmark. It is a small-scale version of NYC Times Square with its screens and lights, and the DIA installation offers itself as an updated and more advanced addition to this spectacle. (It also captures the nation’s attention when the City Hall tower bell is rung on New Year’s Eve).
The overarching idea behind the façade was that of a porous and expressive ‘skin’ between the building and the citizens, one that could function as DI’s ‘face’ and visually brand the city. The media façade changes its visual expression with shifts in intensity, speed, and color according to daily rhythms and seasonal cycles. Beyond this ambient mode, the façade can also be used to highlight and visualize DI’s recognition of larger cultural events such the Eurovision Song Contest or Copenhagen Pride. Finally, on special occasions the media installation has been used as an interactional platform for citizens to draw on the building (the so-called Urban Canvas event ). At this event, a web app was created in which the citizens could ‘paint’ on the surface using their smart phones. At the Culture Night in 2016 in Copenhagen, a special game console was placed in front of the building from which two players played Pong against each other on the side of the building (a so-called Let’s Play event ). Allowing the media façade to become interactive in these events enabled people to have a huge visual and aesthetic impact on the space, thereby momentarily rendering others audience members.
The DIA project was, in contrast to The Humming Wall, a commercial project with a focus on promoting the Confederation of Danish Industry. While it was not conceptualized as a smart city project, it did align itself much closer to the city of Copenhagen’s approach to the smart city. Copenhagen has a broader conceptualization of smart city than Aalborg. Beyond the systemic optimization agenda, there is a focus in Copenhagen on utilizing technologies to understand citizens’ behavior and needs, promote citizen participation and enhance sensorial experiences of the city. The DI building is situated within a zone in the inner city that the municipality promotes as a smart city street lab where new technologies are tested in the urban environment.
Feedback Loops, Interaction Patterns and Types
To begin with we might examine the different types of interaction patterns that arise among the users and the installations. In its simplest form, the interaction at The Humming Wall can be represented as a bi-directional feedback loop from human to system and back again. Through touch gestures the user can activate the wall and the wall responds with sound, vibration, and light. However, the installation can also attract the attention of people passing by and thereby become the initiator. As the installation can be used by multiple users simultaneously, this interaction can go from bi- to multi-directional, as the multiple touch input generates a compound and complex vibro-acoustic response and sensorial experience.
The interaction that occurs at the DIA media façade can be represented in two overall feedback patterns. First, in its passive mode, there is no way for people to affect the system directly. The system reacts to environmental conditions (day/night/seasons) and sometimes, on special occasions, the system responds to larger cultural events, thus initiating a feedback loop on a more abstract level. Second, at the two special events of Let’s Play and Urban Canvas, which we will focus primarily on in this analysis, the media façade is reconfigured to become responsive to user input. Through highly defined protocols, people can interact with the system and manipulate the media façade, thereby co-creating a visual spectacle that engulfs the entire plaza. In doing so, the interaction is mediated directly through the system as well as by its users (participants and audience). Hence, in either of these two cases we find that the installations function as interfaces that not only allow for mediation and feedback between a user and the system, but also between multiple users.
If we look further into the interactions that emerge from these overall feedback loops, we find a variety of ways in which people react to and engage differently with the installations and each other. To categorize these, we take inspiration from Martin Brynskov et al.’s six types of interaction which they found in a study of a light installation in Aarhus, Denmark: pass-and-notice, pass-and-interact, walk-up-and-use, watch-and-join, watch-and-take-over, and return.  The first three categories are particularly useful for discerning how people engage with the installations; however, we have changed them slightly into pass-and-notice (notice), stop-and-watch (become spectator), and walk-up-and-use (become participant) to better suit our purposes.
Using camera tracking, the detailed study on The Humming Wall by Ann Morrison et al. found that 33% of people passing by the installation noticed it.  From our own less systematic observations of DIA, we found that when operating in passive mode little attention seems to be paid to it. The light spectacle, although dynamic, simply becomes part of the ambient light background of the place. However, at the Let’s Play and Urban Canvas events there was a huge increase in attention and most people passing by seemed to notice it (if not noticed directly, then via the crowd already engaged with the media façade as either audience or participant). Among the people who noticed, only a few at The Humming Wall actually did stop-and-watch without further engagement. At the DIA events, by contrast (and without having an exact number), it seemed that most people who noticed did stop, if only for a short while, to see what was going on and observe the visual spectacle. This probably has to do with the fact that the DIA events were much more visually spectacular, as they used the huge building facade as a display for visual feedback. In addition, the spectacle was relatively easy to interpret compared to the less spectacular and more difficult to understand vibration-sound feedback at The Humming Wall. At The Humming Wall, of those people who noticed the installation, 37% physically engaged with it (walk-up-and-use), for example by touching it, walking around it, putting one’s head near it (listening/feeling), or sitting on or leaning against it, thereby reacting actively to the feedback response from the wall.  At the DIA events, only a fraction of passersby engaged further after the initial pass-and-notice or pass-and-stop engagements. This was likely due to the design of the DIA interface with which only a very limited number of people could participate simultaneously. The fact that they had to wait in a queue also discouraged many, we assume.
At both The Humming Wall and the DIA events, people had a tendency to watch (and listen to) the spectacle and observe how others used it from ‘safe distance’ before deciding to join and participate themselves. Here, data from The Humming Wall study show that people tended to approach in pairs and groups, and, especially in groups with children, were more inquisitive and prone to engage physically than individuals.  At both installations, verbal communication occurred not only between people who knew each other (in the groups) but also among strangers. This communication concerned joint exploration and use of the installations: what they could do (in terms of light, vibration, sound), how they functioned, and negotiation of conduct (i.e. turn taking, queuing, acceptable behavior, etc.). Some, especially children, seemed particularly interested in exploring their own role relative to the boundaries of the interaction with the systems, tried to identify the underlying rules of the system, sought ways to stretch or hack it. At The Humming Wall, which had no immediate user instructions and a more open-ended design, people not only observed each other, but also imitated one another other, exchanged experiences and/or simply shared their excitement.  At the Urban Canvas event, where the user interface was more legible and the interaction feedback easier to recognize and thereby manipulate, communication among people to a larger extent concerned the visual experience and the shared light spectacle. At the Let’s Play event, the participants were situated physically next to each other, as this was basically a large-scale public Pong game, and communication tended to focus on how to control the game and the competitive game element itself.
From this overview we see that the installations catalyze different types of interactions. These range from instrumental, when trying to figure out how the installation functions, to social and playful, when negotiating what is understood as meaningful and acceptable use and conduct at the installation sites, to experiential, when talking about and making sense of the sensorial feedback effects of the installations.
Interfacings as Playful and Transformative Friction
Alexander Galloway writes that “interfaces themselves are effects, in that they bring about transformation.”  This is useful because it points out why these installations do not nicely and easily subjugate and interweave into existing situated and spatial practices and meanings of the sites. They are, in a sense, ‘alien spectacles’ because they stand out, and this unexpectedness and incomprehensiveness generate a kind of ‘friction’ in our understanding and use of these spaces. Therefore, much of this interaction emerging from people’s playful and social engagements with the interfaces revolves around attempts to make sense of the installations, their feedback effects, how they enable meaningful manipulation, and how they negotiate codes of conduct and behavior with other people. In this section we pursue a further understanding of the performativity of these installations and how they might generate situated and spatial practices and meanings through what we call ‘playful friction.’
The transformation of a site is, in itself, not remarkable. Installing a merry-go-round, a bench, or any other urban equipment at a site naturally causes some form of transformation in how we think of and use that site.  What makes these installations ‘critical’ is that the merry-go-round and the bench are things that are well-known to most, such that their functions, capabilities, experiential offerings, affordances, inherent logics/codes of usage and typologies likely (re)produce known practices and understandings.
In contrast, the installations we have described work through typologies that are not entirely compatible with people’s understanding of the specific spaces, and thus cannot be immediately subjugated into ordinary practices of using these spaces. We might say that they are artefacts ‘out of frame,’ as they cause friction in our use and understanding.  The DIA installation draws on known elements of playing Pong and drawing on a canvas – playful engagement practices we understand from other contexts – but places them in an alien situation. The Humming Wall is more radical. It works seemingly without clear reference to other known typologies. Its shape and red color call for attention, but it is difficult to identify simply by looking at it.
This lack of recognizability is also evident in the significant effort that people put into simply figuring out the interfaces (by trial and error) and identifying its functions, usages, and limitations. Hence, the kind of transformation that takes place is open-ended and uncertain. When people encountered The Humming Wall, heard its humming noises and perhaps saw others’ playful engagements with it, for instance knocking on it and lying on it, they did not immediately understand exactly what was going on, but they recognized that it was an interface. In more classic urbanist terms, the installations provoke the fundamental question “what is this situation?” that we all face, one that is usually laid to rest thanks to fixed roles, social scripts, and urban typologies.  This question does not normally burden us, but the presence of these interfacing installations may, in fact, do just that. Hence, from this “incomprehensibility of the interface,” as Verhoeff puts it, a space is created, which invites “engaged and playful experimentation.”  Still, this is a social space, and therefore this space can also be considered a “site of contestation”  that not only calls for experimentation but also necessitates negotiation of the meaningful and acceptable ways to engage with the interface. This means that the people who engage with the installation – spectators and participants – both help to discover the inherent logics of the feedback effects and help to create the ‘rules’ that regulate the interactions of people and installations. In this sense, they contribute to what happens.
Here we might ask ourselves if incomprehensibility and uncertainty of a space are qualities that always engender desirable transformation. The answer is clearly no. To understand how the transformation of practices can emerge simply because we place media installations at these sites, we draw on Hookway’s idea of juxtaposing interface with play and games.  Hookway’s points about games and play are in congruence with one of the classic game metaphor inventors, Erving Goffman.  For Hookway, these are comparable and point to the unique ability to temporarily sidestep the everyday world. He writes that “the game come into being through a threshold condition,”  and by this he means we recognize play and games as something separate from everyday life, and accept that within the ‘playground’ special rules apply. This threshold condition plays a double role as it both “delimits the space for a kind of inhabitation and opens up otherwise unavailable phenomena, conditions, situations, and territories for exploration, use, participation, and exploitation.”  Hence, upon becoming a player who inhabits the playground and thereby understands and accepts the game as something apart from the everyday world, one is endowed with what Hookway calls a “sacred status.”  This status allows one to enter a make-believe in-between in which exploration of otherness, performances, practices, meanings, and actions can occur.
With this analogy, we can think of the installations as engendering a temporary ‘playground’ that imposes a set of rules. These rules momentarily dampen the everyday world’s social conventions, inhibitions, fear of embarrassment, etc. and allow for experimentation of one’s own actions, bodily engagements and relations with the installations and others. We recognize this in people when they interact with others with ease and feel less insecure in approaching strangers. We saw evidence of this when people playfully embodied acts of exploration and participation at the two installations, for example, when jumping in front of The Humming Wall to get feedback or when loudly exhibiting discontent by losing a game of Pong on the façade of the DIA building. Hookway also writes that “[a]s the player of a game or the user of an interface, one never fully enters into a [game or playground]; rather one is held at its threshold.”  Thus, he refers to the liminal character of play and the fact that we never lose ourselves completely and permanently to the game we play because we always have one foot in the everyday world. This means that social conventions and inhibitions never fully evaporate but are dampened through play as we keep a foot in the everyday world. Becoming a player and crossing this threshold of the installation space is much easier for children than for adults. At The Humming Wall, as mentioned above, groups with children were more disposed to move from stop-and-watch to walk-up-and-use. However, this also means that the actions performed at the installation are not kept within the installations space but have an effect that ‘spills over’ into the everyday world. In this light, the installations as interfaces become “a productive moment of encounter embedded and obscured with in the use of technology.”  This might be as banal as witnessing people playing at the installation, which might incrementally shift understandings of what might happen in this place, what kind of place it is, and how we might use the place in the future. Thus, the capacity of the installations is to congregate or bring about ‘publics.’  As such, these ‘publics’ work as facilitators of “temporary congregations”  and fleeting public assemblages, or what might be termed “mobile agoras.”  Hence, through this small window of uncertainty and open-endedness framed within these threshold conditions, the installations are able to engender a space of friction for people to congregate around experimentation with extraordinary (and perhaps even transgressive) practices such as lying on a vibrating surface in a park or playing pong on a huge building façade.
Concluding remarks – zooming back out
Martijn de Waal writes that “the function of the urban public sphere” is that “it brings city dwellers together spatially who then collectively form a (temporary) public.”  The installations we have examined exemplify how technologies might augment and even enhance the ability of public urban spaces to foster and support the formation of urban publics. What we see at the installation sites is the shifting formation and dispersions of publics consisting of people who know each other as well as strangers, all of whom become co-present around the installation. Furthermore, publics are not passive audiences; they toggle between being active listeners and performers.  People interacting on different levels mediate the installations (from simply taking notice of each other, to chatting, to playing against each other, to co-creating ‘music’).
We might easily assume a positive bias towards the potential effects and outcomes of The Humming Wall and the DIA installation. We might expect that they improve the formation and support of social interactions, publics and ultimately enhance public urban spaces as sites of rich sensorial experience. However, bringing this discussion back to our intention and ambition with feedback urbanism, we wish to maintain a critical stance. De Waal states that the interface is not a neutral environment, as it “partly determine[s] how a possible interchange or harmonization comes about.”  Using the game analogy, we have sought to elucidate how rules or threshold conditions govern the use and appropriation of these installations. Before celebrating these types of interactive installations as enhancements of public urban spaces, we must also ask ourselves who makes/who benefits.
As should be clear from this paper we advocate for a more balanced approach to smart city technologies. Since the corporate smart city focuses too much, in our opinion, on top-down, large-scale and scalable solutions, there is a need to re-emphasize the local and the human dimension. This also has to do with the fact that the goals and issues with which we are dealing are large-scale, networked, and often global in nature. Conversely, we see that there is also a growth of more local and bottom up smart city initiatives (i.e. hackathons, maker spaces and fablabs). Here the general critique is that there is no awareness of scalability and that these initiatives cannot be easily transported, replicated or scaled, and that this effectively means that their transformative capacity is equally grounded in the specific situation and places (and therefore not ambitious enough in relation to larger issues and urban problems). Indeed, Townsend elucidates this ‘paradox’ of empowerment and scalability.  This may be true, but it infers that we impose a specific logic and agenda working towards finding solutions for large-scale issues onto these more bottom-up approaches to smart cities. A greater awareness of how these initiatives connect to larger issues and more global contexts is needed, which could be approached through the notion of scalability (but also transferability, role modelling). We advocate a move away from the idea of a master narrative in which everything should and could fit into a larger scheme. In a sense, this streamlining and mainstreaming of all components and citizens in the smart city is exactly the logic of the corporate smart city. Instead, we think that the concept should allow for diversity, inconsistency, incompleteness, and multiplicity for people to get involved, co-develop and find ownership and relevance in their engagement with technologies and data. There seem to be competing aims or at least a fight for importance in (a) solving grand problems, and (b) creating a more livable environment and foster civic engagement.
Returning to the feedback urbanism framework, we offer the following points in conclusion. The Humming Wall and DIA are both aggregated actor-networks and assemblages dissolving strict divisions between subject/object, fixed/fluid, global/local. Theoretically and conceptually, they invite flat ontologies and understandings that accept more symmetric relations between technology, sociality, humans, and the built environment. The Humming Wall and DIA are both multi-scalar spatial phenomena (sensing bodies-global networks) that connect to new ways of understanding multi-sensorial, embodied, affectual, and situated practices. As such, they afford changing subject-positions, networked selves and differential subjectivities. They are performative spaces and temporary experiments that open up a different conversation between research and the arts. The Humming Wall and DIA both illustrate how the digital and physical ‘melt together’ in complex processes of hybridization. Finally, with the feedback urbanism framework we wish to point to the proliferation of performative spaces and temporary experiments that are at the heart of the two installation projects investigated in this paper. From a mostly positive point of view we may highlight the fascinating potentials of using media technologies to create playful infrastructures that foster social interaction and the formation of publics in urban spaces. However on a more sober note, we also feel it is important to understand these new digitally mediated installations and public spaces as expressions of new complex power-geometries. Power-geometries of surveillance, control, and less democratic practice are also within their potential – less fun and play indeed!
Simon Wind has a master in Architecture and Urban Design and a PhD in Mobilities Studies. He currently works as a mobility planner at the City of Aarhus, the second largest city in Denmark. Prior to this, he has taught and researched 8 years at Aalborg University, Denmark. His research interests span everyday mobilities, urban mobility planning, smart cities and mobile ethnographic methods. He has published his research in international journals of Mobilities and Applied Mobilities as well as a number of academic books.
Ole B. Jensen is Professor of Urban Theory at the Department of Architecture, Design and Media Technology, Aalborg University (Denmark). BA in Political Science, MA in Sociology, PhD in Planning, and Dr. Techn. in Mobilities. Deputy Director, co-founder and board member at the Centre for Mobilities and Urban Studies (C-MUS) and Director of the research cluster in ‘Mobility and Tracking Technology’ (MoTT). Main research interests: Urban Mobilities, Mobilities Design, and Networked Technologies. He is the author of Staging Mobilities, Routledge, 2013, and Designing Mobilities, 2014, Aalborg University Press, the Editor of the four-volume collection Mobilities, Routledge, 2015, author (with Ditte Bendix Lanng) of Urban Mobilities Design, Urban Designs for Mobile Situations, 2017, Routledge, and co-editor (with Mimi Sheller and Sven Kesselring) of Mobilities and Complexities, Routledge, 2018.
Notes and References
 Ole B. Jensen and Nicola Morelli, “Critical Points of Contact – Exploring Networked Relations in Urban Mobility and Service Design,” Danish Journal of Geoinformation and Land Management 113, no. 46 (2011): 36-49.
 Michael Batty et al., “Smart Cities of the Future” (working paper, Centre for Advanced Spatial Analysis (CASA), no. 188, ISSN 1467-1298, UCL, London, 2012); Robert Kitchin and Martin Dodge, Code/Space. Software and Everyday Life (Cambridge MA: MIT Press, 2011).
 Robert G. Hollands, “Will the Real Smart City Please Stand Up?” City 12, no. 3 (2008): 303-320; Allan Greenfield, Against the Smart City (New York, NY: Do Projects, 2013); Drew Hemment and Anthony Townsend, Smart Citizens (Manchester: FutureEverything Publications, 2013); Anthony Townsend, Smart cities: Big Data, Civic Hackers, and the Quest for a New Utopia (New York, NY: W.W. Norton & Company, 2013); Saskia Sassen, “Urbanising Technology,” in Urban Age Electric City Conference, ed. Ricky Burdett and Phillipp Rode (London: LSE Cities, 2012).
 Saskia Sassen, “Urbanising Technology,” 14.
 Ola Söderström, Till Paasche and Francisco Klauser, “Smart Cities as Corporate Storytelling,” City 18, no. 3 (2014): 307-320; Martijn de Waal, The City as Interface: How Digital Media are Changing the City (Rotterdam: nai010 publishers, 2014).
 Michel de Lange, “The Playful City: Using Play and Games to Foster Citizen Participation,” in Social Technologies and Collective Intelligence, ed. Aelita Skaržauskienė (Vilnius: Mykolas Romeris University, 2015), 427.
 Malcolm Tait and Ole B. Jensen, “Travelling Ideas, Power and Place: The Cases of Urban Villages and Business Improvement Districts,” International Planning Studies 12, no. 2 (2007): 107-127.
 Ole B. Jensen, “Drone City – Power, Design and Aerial Mobility in the Age of the ‘Smart City,’” Geographica Helvetica+ 71, no. 2 (2016): 68.
 Maarten Hajer and Ton Dassen, Smart about Cities: Visualizing the Challenge for 21st Century Urbanism (Rotterdam: NAi 010, 2014).
 “Meaning of interface,” Merriam-Webster, accessed June 20, 2017, https://www.merriam-webster.com/dictionary/interface&spf=73.
 Alexander R. Galloway, The Interface Effect (Cambridge, UK: Polity, 2012), 30.
 Branden Hookway, Interface (Cambridge, MA: MIT Press, 2014), 1.
 Jensen and Morelli, “Critical Points of Contact,” 38.
 Galloway, The Interface Effect, vii.
 Ibid., 31.
 Nanna Verhoeff, “Interfaces of Media Architecture,” in Media Architecture: Using Information and Media as Construction Material, ed. Alexander Wiethoff and Heinrich Hussmann (Berlin and Boston, MA: De Gruyter Mouton, 2017), 45-46.
 Ibid., 46.
 Malcolm McCullough, Digital Ground: Architecture, Pervasive Computing, and Environmental Knowing (Cambridge, MA: MIT Press, 2004).
 Jan Gehl, Cities for People (Washington, D.C.: Island Press, 2010); Erwing Goffman, Behavior in Public Places: Notes on the Social Organization of Social Gatherings (New York, NY: The Free Press, 1963); Jane Jacobs, The Death and Life of Great American Cities (New York, NY: Vintage Books, 1961); Saskia Sassen, “Urbanising Technology”; Richard Sennett, The Uses of Disorder: Personal Identity and City Life (New York, NY: Faber & Faber, 1996).
 See for instance Michel de Lange, “The Playful City” or Adriana de Souza e Silva and Larissa Hjort “Playful Urban Spaces: A Historical Approach to Mobile Games,” Simulations and Gaming 40, no. 5 (2009): 602-625.
 Charles Montgomery, Happy City: Transforming Our Lives Through Urban Design (New York, NY: Farrar, Straus, Giroux, 2013).
 Bjarke Ingels Group (BIG), Yes Is More: An Archicomic on Architectural Evolution (Copenhagen: BIG ApS, 2009).
 Ole B. Jensen, “On the Move – On Mobile Agoras, Networked Selves, and the Contemporary City,” in The Routledge Urban Media Companion, ed. Zlatan Krajina and Deborah Stevenson (London: Routledge, forthcoming); Ole B. Jensen and Bo Stjerne Thomsen, “Performative Urban Environments: Increasing Media Connectivity,” in Mediacity: Situations, Practices and Encounters, ed. F. Eckardt (Berlin: Frank & Timme, 2008), 407-429.
 Ann Morrison, Cristina Manresa-Yee and Hendrik Knoche, “Vibrotactile Vest and The Humming Wall: ‘I like the hand down my spine,’” in Interacción 2015: Proceedings of the XVI International Conference on Human Computer Interaction, 3:1-3:8 (New York, NY: Association for Computing Machinery, 2015), 3.
 Ann Morrison et al., “The Humming Wall: Vibrotactile and Vibroacoustic Interactions in an Urban Environment,” in Proceedings of the 2016 ACM Conference on Designing Interactive Systems (New York, NY: Association for Computing Machinery, 2016), 818-822.
 Morrison et al., “The Humming Wall,” 818.
 The project also included a vibro-tactile body-worn vest which added yet another level of experience and interaction to the installation. While the wall and the vest was designed as a whole, the wall in itself also worked as a standalone installation. In this analysis, we will therefore focus solely on the wall (for more information on the vest see Morrison, Manresa-Yee and Knoche, “Vibrotactile Vest and The Humming Wall.”
 See Ann Morrison, “Humming Wall and Wearable Vest Interaction at Utzon Park,” Vimeo, October 17, 2014, video, 2:52, https://vimeo.com/109226990.
 Morrison et al., “The Humming Wall.”
 See “DIA Lights,” Kollision, May 9, 2013, http://kollision.dk/en/IH.
 See Kollision, “Dia Lights,” Vimeo, May 10, 2013, video, 2:05, https://vimeo.com/65938382.
 See Kollision, “Urban Canvas,” Vimeo, March 14, 2014, video, 01:38, https://vimeo.com/89146997.
 Martin Brynskov et al., “Staging Urban Interactions with Media Facades,” in Human-Computer Interaction – INTERACT 2009, vol. 5726, eds. T. Gross et al. (Berlin: Springer, 2009), 154-167.
 Morrison et al., “The Humming Wall,” 820.
 Galloway, The Interface Effect, vii.
 See for instance Gehl, Cities for People or William H. Whyte, City: Rediscovering the Centre (Philadelphia, PA: University of Pennsylvania Press, 1988).
 Erwing Goffman, Frame Analysis: An Essay on the Organization of Experience (Boston, MA: Northeasthern University Press, 1974).
 Erwing Goffman, The Presentation of Self in Everyday Life (New York, NY: Penguin, 1959).
 Verhoeff, “Interfaces of Media Architecture,” 55.
 Hookway, Interface, ix.
 Ibid., 32.
 Erwing Goffman, Encounters: Two Studies in the Sociology of Interaction (New York, NY: The Bobbs-Merrill Company Inc., 1961).
 Hookway, Interface, 32.
 Ibid., 5.
 Ibid., 32.
 Ibid., 38.
 Ibid., ix.
 John Dewey, The Public and its Problems (New York, NY: Holt, 1927); Bruno Latour and Peter Weibel, Making Things Public: Atmospheres of Democracy (Cambridge, MA: MIT Press, 2005).
 Ole B. Jensen, Staging Mobilities (London: Routledge, 2013), 4.
 Ole B. Jensen, “On the Move.”
 De Waal, The City as Interface, 17.
 Ibid., 13.
 Ibid., 22.
 Townsend, Smart Cities.
Batty, Michael, Kay Axhausen, Giannotti Fosca, Alexei Pozdnoukhov, Armando Bazzani, Monica Wachowicz, Georgios Ouzounis, and Yuval Portugali. “Smart Cities of the Future.” Working paper, Centre for Advanced Spatial Analysis (CASA), no. 188, ISSN 1467-1298, UCL, London, 2012.
Bjarke Ingels Group (BIG). Yes Is More: An Archicomic on Architectural Evolution. Copenhagen: BIG ApS, 2009.
Brynskov, Martin, Peter Dalsgaard, Tobias Ebsen, Jonas Fritsch, Kim Halskov, and Rune Nielsen. “Staging Urban Interactions with Media Facades.” In Human-Computer Interaction – INTERACT 2009, vol. 5726, edited by T. Gross, J. Gulliksen, P. Kotzé, L. Oestreicher, P. Palanque, R.O. Prates, M. Winckler, 154-167. Berlin: Springer, 2009.
De Lange, Michel. “The Playful City: Using Play and Games to Foster Citizen Participation.” In Social Technologies and Collective Intelligence, edited by Aelita Skaržauskienė, 426-433. Vilnius: Mykolas Romeris University, 2015.
De Souza e Silva, Adriana, and Larissa Hjort. “Playful Urban Spaces.” Simulations and Gaming 40, no. 5 (2009): 602-625.
De Waal, Martijn. The City as Interface: How Digital Media are Changing the City. Rotterdam: nai010 publishers, 2014.
Dewey, John. The Public and its Problems. New York, NY: Holt, 1927.
Galloway, Alexander R. The Interface Effect. Cambridge, UK: Polity, 2012.
Gehl, Jan. Cities for People. Washington, D.C.: Island Press, 2010.
Greenfield, Allan. Against the Smart City. New York, NY: Do Projects, 2013.
Goffman, Erwing. Behavior in Public Places: Notes on the Social Organization of Social Gatherings. New York, NY: The Free Press, 1963.
Goffman, Erwing. Encounters: Two Studies in the Sociology of Interaction. New York, NY: The Bobbs-Merrill Company Inc., 1961.
Goffman, Erwing. Frame Analysis: An Essay on the Organization of Experience. Boston, MA: Northeasthern University Press, 1974.
Goffman, Erwing. The Presentation of Self in Everyday Life. New York, NY: Penguin, 1959.
Hajer, Maarten, and Ton Dassen. Smart about Cities: Visualizing the Challenge for 21st Century Urbanism. Rotterdam: Nai 010, 2014.
Hemment, Drew, and Anthony Townsend. Smart Citizens. Manchester: FutureEverything Publications, 2013.
Hollands, Robert G. “Will the Real Smart City Please Stand Up?” City 12, no. 3 (2008): 303-320.
Hookway, Branden. Interface. Cambridge, MA: MIT Press, 2014.
Jacobs, Jane. The Death and Life of Great American Cities. New York, NY: Vintage Books, 1961.
Jensen, Ole B. “Drone City – Power, Design and Aerial Mobility in the Age of the ‘Smart City.’” Geographica Helvetica+ 71, no. 2 (2016): 67-75.
Jensen, Ole B. “On the Move – On Mobile Agoras, Networked Selves, and the Contemporary City.” In The Routledge Urban Media Companion, edited by Zlatan Krajina and Deborah Stevenson. London: Routledge, forthcoming.
Jensen, Ole B. Staging Mobilities. London: Routledge, 2013.
Jensen, Ole B., and Bo Stjerne Thomsen. “Performative Urban Environments: Increasing Media Connectivity.” In Mediacity: Situations, Practices and Encounters, edited by F. Eckardt, 407-429. Berlin: Frank & Timme, 2008.
Jensen, Ole B., and Nicola Morelli. “Critical Points of Contact – Exploring Networked Relations in Urban Mobility and Service Design.” Danish Journal of Geoinformation and Land Management 113, no. 46 (2011): 36-49.
Kitchin, Robert, and Martin Dodge. Code/Space. Software and Everyday Life. Cambridge MA: MIT Press, 2011.
Kollision. “DIA Lights.” May 9, 2013. http://kollision.dk/en/IH.
Kollision. “Dia Lights.” Vimeo, May 10, 2013. Video, 2:05. https://vimeo.com/65938382.
Kollision. “LET’S PLAY.” October 14, 2016. http://kollision.dk/en/lets-play.
Kollision. “LET’S PLAY.” Vimeo, October 16, 2016. Video, 01:45. https://vimeo.com/187577445.
Kollision. “Urban Canvas.” Vimeo, March 14, 2014. Video, 01:38. https://vimeo.com/89146997.
Latour, Bruno, and Peter Weibel. Making Things Public: Atmospheres of Democracy. Cambridge, MA: MIT Press, 2005.
Merriam-Webster. “Meaning of interface.” Accessed June 20, 2017. https://www.merriam-webster.com/dictionary/interface&spf=73.
McCullough, Malcolm. Digital Ground: Architecture, Pervasive Computing, and Environmental Knowing. Cambridge, MA: MIT Press, 2004.
Montgomery, Charles. Happy City: Transforming Our Lives Through Urban Design. New York, NY: Farrar, Straus, Giroux, 2013.
Morrison, Ann. “Humming Wall and Wearable Vest Interaction at Utzon Park.” Vimeo, October 17, 2014. Video, 2:52. https://vimeo.com/109226990.
Morrison, Ann, Cristina Manresa-Yee, and Hendrik Knoche. “Vibrotactile Vest and The Humming Wall: ‘I like the hand down my spine.’” In Interacción 2015: Proceedings of the XVI International Conference on Human Computer Interaction, 3:1-3:8. New York, NY: Association for Computing Machinery, 2015.
Morrison, Ann, Cristina Manresa-Yee, Walther Jensen and Neda Eshraghi. “The Humming Wall: Vibrotactile and Vibroacoustic Interactions in an Urban Environment.” In Proceedings of the 2016 ACM Conference on Designing Interactive Systems, 818-822. New York, NY: Association for Computing Machinery, 2016.
Sassen, Saskia. “Urbanising Technology.” In Urban Age Electric City Conference, edited by Ricky Burdett and Phillipp Rode. London: LSE Cities, 2012, 12-14.
Sennett, Richard. The Uses of Disorder: Personal Identity and City Life. New York, NY: Faber & Faber, 1996.
Söderström, Ola, Till Paasche and Francisco Klauser. “Smart Cities as Corporate Storytelling.” City 18, no. 3 (2014): 307-320.
Tait, Malcolm, and Ole B. Jensen. “Travelling Ideas, Power and Place: The Cases of Urban Villages and Business Improvement Districts.” International Planning Studies 12, no. 2 (2007): 107-127.
Townsend, Anthony. Smart cities: Big Data, Civic Hackers, and the Quest for a New Utopia. New York, NY: W.W. Norton & Company, 2013.
Verhoeff, Nanna. “Interfaces of Media Architecture.” In Media Architecture: Using Information and Media as Construction Material, edited by Alexander Wiethoff and Heinrich Hussmann, 43-58. Berlin and Boston, MA: De Gruyter Mouton, 2017.
Whyte, William H. City: Rediscovering the Centre. Philadelphia, PA: University of Pennsylvania Press, 1988.