New directions in the theorisation of temporary urbanisms: Adaptability, activation and trajectory

This article rethinks processes and practices of urban temporariness in a more agile, localised and context-specific way, where rhythms and dynamics of the everyday are clearly acknowledged. It discusses the directions of research required to theorise ‘temporary urbanisms’. To do so, three overlapping literatures are used: Lefebvrian conceptualisations of rhythms and the everyday; evolutionary analyses of path of change and path creation; and geographies of architecture. This article recognises that although temporariness is (evidently) a universal urban condition, diverse discursive and practical dynamics exist directing urban temporariness along particular channels and shaping space significantly while impacting people’s living environments.


I Introduction
Analysing urban environments is an incredibly complex task as it involves deconstructing various temporal and spatial dynamics affecting people and spaces. Looking back at how cities have been shaped and reshaped along history, there are two important points to consider. First, cities result from a constant process of construction and reconstruction, based on redundancy and reuse (Andres, 2009;Bryson, 1997). Second, the built environment is never fully stable and completed; by essence the 'unfinished' is part of the urban condition (Lerup, 1977).
Building on these preliminary points, and perhaps paradoxically, it is often the case that the process of designing and developing cities -either referred to as urban planning or urbanism -is associated with formal and transformative mechanisms of change and maintenance of existing and future built environments. Such interventions share the goal of a 'finished' outcome, aiming to shape the future, leaving limited space for flexibility and to account for more iterative, sometimes informal, processes of urban making. The latter include forms of reuse, the 'unfinished', and 'inbetween' or 'meanwhile' stages within processes of creative urban (re)construction (what we refer to through the article as 'temporary urbanisms'). This is a key paradox for cities: how to deal with or plan for the 'temporary' in professions that so often seek to plan so meticulously for the future. To engage with this paradox, moreover, directly impacts how we think and rethink cities as liveable places embedded within various temporalities of change, both permanent and impermanent. This article aims to rethink and develop a conceptual language around practices and process of urban temporariness.
Indeed, notwithstanding our initial comments about how (for instance) urban planners desire a 'finished' product, this paradox is further complicated by an arguably less common feature of place-making (Bishop, 2019): designing-in flexibility. This is an important feature of place-making and has been a fairly longstanding trend in the field of urban studies research, particularly in terms of transient projects, led by various stakeholders, from artists to community groups, in a bottom-up way, and more recently local authorities and developers (top-down) (Andres and Zhang, 2020;Bishop and Williams, 2012;Oswalt et al., 2017;Talen, 2012). A key consideration has been their 'everyday' nature (Oswalt et al., 2017;Temel and Haydn, 2006) and their ephemeral status, with diverse consequences for their surrounding physical and social environments. Thus, temporary uses and projects are not merely seen as informal or organic responses to urban challenges but may form part of more formal reimaginings of city space. This trend has driven reflections on the management of the duration of urban development, where the temporary is understood as a tool for sequencing changes in periods of uncertainties (Madanipour, 2017(Madanipour, , 2018. In spite of such work, and conceptions of time in/of the urban more generally, debates about the facets of urban temporariness have tended to be piecemeal, discipline-specific and often case-study-based. To generalise, most of the discussions have been characterised by an interest in making intentional but temporary interventions into urban spaces. However, there is, for instance, a divide between (crudely put) top-down, 'planned' (policymaker-/professional-led) interventions such as temporary food and retail parks in containers, pop-up shops or workshops in empty commercial units, and bottom-up interventions, which may be 'unplanned', activist-or community-led (e.g. temporary community gardens, playgrounds, cultural spaces set up in either unoccupied buildings, open space or temporary structures on vacant lands). Additionally, most conceptual focus is afforded to the considerations of duration -the temporal characteristics of the 'in-between' and the 'what's next?', rather than on adopting a more systemic and integrated theorisation of the diversity of temporary processes of place-making and their wider implications for shaping cities over the longer term. There is a lack of a systematic conceptual language that can embrace the diversity of temporary uses and could help urban scholars better understand and unwrap complex and multi-temporal built environments, particularly with a view to better articulating everyday dynamics with the wider social and economic process of urban placemaking (shaped around a vision for the future).
To address these lacunae, this article thus aims to rethink processes and practices of urban temporariness in a more agile, localised and context-specific way, where rhythms and dynamics of the everyday are more clearly acknowledged. To achieve this, we build upon the existing concept of temporary urbanism (Andres et al., 2019;Andres and Zhang, 2020;Madanipour, 2017) and discuss the directions of research required to theorise 'temporary urbanisms'. The contribution of this article is to recognise that although temporariness is (evidently) a universal urban condition, diverse discursive and practical dynamics exist that direct urban temporariness along particular channels and shape space differently but significantly while impacting people's living environments.
Our re-theorisation of temporary urbanisms encompasses processes, practices and policies of and for spatial adaptability, which allow the activation of a space in perceived need of transformation, thus leading to paths of change through a trajectory of transformation. We extract and develop these three terms -activation, adaptability and trajectory -as the building blocks for a theory of urban temporariness, initially out of our critique of current debates about temporary urbanisms and their focus on temporal duration (first section). We then establish in the second section our theoretical language, alongside a set of challenges and questions with which future scholars might engage. To do so, we mobilise three theoretical framings that help extend the conceptual and empirical purchase of adaptability, activation and trajectory, either individually or taken together: Lefebvrian understandings of the everyday rhythms characterising interventions into the social and/or infrastructural elements of the urban fabric; evolutionary analyses of path creation, affording insights into the mechanisms of transformation, drivers and actors of change; and recent work on geographies of architecture, critically reflecting on the built forms embedded within the trajectories of urban spaces. In so doing, it is our goal not only to more formally articulate such existing 'dynamics' but to critically question some of the assumptions that guide them. Finally, we use the concluding section to reflect on the broader implications of our theorisation of temporariness and what this means for rethinking cities' liveabilities. This article combines the distinct but complementary expertise of the two authors in the areas of urban planning, urban studies and social and cultural geographies. Together, our work shares underpinnings in qualitative and case-study-based approaches, and, substantively, we combine a long-standing interest in key, contemporary processes of urban transformations around the world in which temporary urbanisms are playing a crucial role. Andres's work draws upon a range of research conducted in the last 15 years in various contexts (Europe, Brazil, South and East Africa), involving in total over 300 interviews with key stakeholders (including users, policymakers, developers, planners, communities) coupled with participatory observations and archive work. Kraftl's work draws upon several research projects conducted over the past decade, in the UK and in Brazil, which have focused on the experiences of diverse stakeholders who design, deliver and/or live in large-scale, master-planned urban developments. This line of research has involved qualitative, often ethnographic research with over 300 children and young people (aged 8-25), plus over 100 other stakeholders including children's families, community leaders, local and national policymakers and private developers.

II Framing a Re-Interrogation of Temporary Urbanisms
Through this section, we review and develop conceptual framings of temporary urbanisms, building upon gaps within contemporary interpretations of this term, and demonstrating why a new conceptual language based upon a pluralistic use of 'temporary urbanisms' is needed as to unwrap and integrate the diverse temporary dynamics of everyday urban making. In building our conceptual framework, we make three observations: about the predominance of duration in especially recent work on temporary urbanisms; about the proliferation of empirical and conceptual themes in wider work, as temporary urbanisms have gained further attention; and, as a result, among a range of rich, local, empirical studies, about the need for a more systematic framework -here, focused on activation, adaptability and trajectory -that is implicit within, but could be far betterdevelop than, the use of these terms in extant scholarship.
First, ephemerality, transience, liminality, pop-up, tactical, DIY have all been terms used to characterise temporary projects (see Harris, 2015 for a review). The conceptual focus is on the temporary duration of a use, approach and initiative set up on specific spaces. Duration here is fully enmeshed with the concept of time. Temporary urbanisms connect to temporalities and the everyday (Madanipour, 2017). They are 'based on events that seem to be random, outside of the normal rhythm of things, disrupting the settled habits of society and disregarding the routines that regulate everyday life' (Madanipour, 2017: 12). The concept of time and 'temporary' duration are used as an umbrella framework to deconstruct the spatial and social economic components of temporary uses. This complements case-study-based work that looked into how neighbourhoods or sites have been transformed because of temporary activities (e.g. Colomb, 2012) through different paths of transformation, highlighting the connection between temporary interventions, contexts of disruption and the need to rethink spaces (e.g. see Lehtovuori and Ruoppila, 2017;Tardiveau and Mallo, 2014).
Second, beyond -although often still cognisant of -questions of duration, scholars have considered diverse empirical and conceptual themes. Greatest attention has been paid to 20th-and 21st-century transformations that led to differently scaled phases of urban renewal (Bishop and Williams, 2012;Oswalt et al., 2017;Talen, 2012). Most of those uses have been scrutinised in two ways: first with regard to how they responded to specific needs, shocks, phases of transitions, that is, how they appeared as a solution to dysfunctions within the process of urban making, addressing the everyday needs of artist, businesses or communities (e.g. see Mould, 2014); second, in terms of analyses of the actors leading those temporary projects. Undeniably, temporary creative initiatives led by artists or individuals have been in the core of many studies, often due to conflictual and sometimes illegal processes of appropriation of buildings (e.g. see Colomb, 2012;Groth and Corijn, 2005;Nemeth and Langhorst, 2014); in parallel, temporary experimentations arising in spaces experiencing development deadlocks were also scrutinised when such initiatives settled within a context of laissez-faire, where both landowner and local authorities saw them as 'better than nothing' solutions (Andres, 2013).
As such, most research on temporary uses initially scrutinised bottom-up processes, which, while acknowledging the risk of romanticising temporary uses (such as squatting), have allowed city authorities to promote out-of-thebox thinking that challenges formal planning arrangements (Tonkiss, 2013). Neoliberal urban planning policies, combined austerity urbanism (Tonkiss, 2013), added further drivers to the emergence of temporary urbanisms. Bishop and Williams (2012) were some of the first scholars to explore the emerging nature of this shift where local authorities and developers started to experiment with the use of temporary gardens, pools or commercial outlets (within softer and looser planning frameworks and designs) to deliver wider transformation agendas outside of a deadlock situation (see also Bishop, 2015). Such temporary urbanisms, here formalised as top-down dynamics, are not merely seen as informal responses to urban challenges but form part of more formal reimaginings of city space. This trend has, in turn, driven reflections on the management of the duration of urban development, where the temporary is understood as a tool for sequencing changes in periods of uncertainties (Madanipour, 2017(Madanipour, , 2018.
Third, most of the studies that have explored such bottom-up/top-down process have been context-based case-studies. They have generated significant insights about the differential nature of temporary urbanisms, the diversity of urban contexts, actors involved and on how they have been impacting spaces, people and the wider policy and planning environment. While valuable, such studies have not been systematically analysed, compared or theorised. Thus, fairly disparate scholarship on temporary urbanisms lacks a more coherent conceptual framework through which key processes -such as activation, adaptability and trajectory -might be understood.
Many of the above studies at least implicitly signal that temporary urbanisms (nearly) always enable forms of activation: in other words, whomever spearheads them, they lead to spaces, people and a wider urban environment becoming operative -or active -again. Significantly, literatures on temporary urbanisms have focused on urban areas neglected by the state, capital and planning (Oswalt et al., 2017). They have scrutinised the dynamics of temporary transformation in cities like Berlin (Colomb, 2012), Marseille (Andres, 2011(Andres, , 2013, Brussels (Groth and Corijn, 2005), Dublin (Moore-Cherry and Mccarthy, 2016) or Turin (Rota and Salone, 2014), where market mechanisms were gripped (Harris, 2015;Tardiveau and Mallo, 2014). Here, temporary urbanisms were responses to uncertainty and to private and public sector failure with citizens compensating for uses/facilities they miss . Thus, temporary urbanisms may be viewed as mechanisms for activation -whether improving the material infrastructures of places or reenlivening spaces deemed 'vacant' or 'unproductive'. This concept of activation is critical as it allows a movement beyond the bottomup/top-down distinction -focusing on what, where or who is activated (and potentially divergent views of that activation). Of course, an outcome here can be the temporary being made permanent. What is apparent though is that the activation occurs through a range of actors collaborating and experimenting with new practices to initiate transformation. Going back to the idea of citizen-led innovation as responses to failure, activation through temporary urbanisms provides an opportunity for the formation of a local network of people developing a solution then triggering urban change. The process of 'activation' also acknowledges, but sidesteps, questions of temporary duration and hence diversity of permanent and nonpermanent temporalities within the process of urban making. However, beyond the above (implicit) acknowledgements that activation matters, the concept -like those of adaptability and trajectory -requires considerable development.
In terms of adaptability, it is here the versatile but also flexible nature of temporary urban interventions (similar to the 'pop-up' -see Harris, 2015) that is recognised. Building on notions of activation, temporary urbanisms have been positioned as site-and context-specific responses to the needs of local spaces and/or people, in contexts of significant transition and transformation within a specific area. What that research (again the examples cited in the previous paragraph implicitly touch on this) has in common is associating temporary urbanisms with the prospect of offering a substitute to traditional forms of place-making that might be more appropriate to the everyday, material needs of a place, within its wider socioeconomic contexts. What links temporary urbanisms together here then is the concept of adaptability: both in terms of the adaptability of an intervention and of individuals taking ownership of a space and adapting it and in terms of the (again potentially contested) quality and ability of a space to be modified. Again moving beyond notions of temporary duration -not least with its attention to the everyday, multiscalar, material spatialities of a 'place' -in tandem with the notion of activation, the concept of adaptability pushes towards a more agile understanding of temporary urbanisms which directly connects with the quotidian nature of temporary urbanisms and the liveability of urban spaces in which such experimentations settle in. However, as our brief, parenthetical references to contestation attest, acknowledging diversity, power relations and conflict in and of cities is fundamental: any conceptualisation of temporary urbanisms needs itself to be sufficiently malleable to sharp variations between and within diverse urban contexts, and in viewpoints as to what 'needs' changing, and how.
Finally, and with the notion of trajectory in mind, recent scholarship on temporary urbanism has begun to recognise its diversity, both spatial and temporal. For instance, cognisant of the rise and diversification of temporary uses, Bishop and Williams (2012) highlight complexities and ambiguities of 'temporary urbanisms' as formal and/or informal; legal and/or illegal; planned and/or spontaneous; long-lasting and/or short-term; and funded in diverse ways. Encompassing these and other features, which again include but extend beyond notions of temporal duration, we understand trajectory as the path followed by a 'place' concerned with temporary urbanisms, through various forces and dynamics in place (actors, planning policies, development strategies, etc.). This path may be linear as it runs day after day, but it is fundamentally iterative, adaptable and dependent upon different forms of activation. The notion of trajectory is also attuned to the (possible) changes in everyday rhythms, socioeconomic contexts and material circumstances of any place -in other words, that which is imagined, planned and manifested at a site experiencing a temporary intervention, where, and how (not just when). Trajectory also implies a direction of travel for the temporary project which may be planned, envisioned, or not, which as an outcome may be how to make the project permanent.
Bringing those three concepts together and elevating them as a threefold framework for re-theorising temporary urbanisms is for us a way to address existing gaps and to develop a common (although of course not universal) language that could help to describe similar dynamics, albeit as differentially expressed. As we outline below, this way of apprehending temporary urbanisms promotes analyses of the articulation of everyday processes of path creation/change and architectural and/or infrastructural changes, with 'wider' socioeconomic spatio-temporalities of urban life. These spatio-temporalities may or may not cohere and may be contested -but range from questions of place-making and place-branding to senses of belonging and community cohesion, and from the ambience and history of an area to shifting land and property values, hence querying cities' liveabilities. Therefore, as we will argue later, temporary urbanisms are, in this logic, positioned as an anticipatory narrative and strategy that can enable preparedness strategies for future challenges, both economic and social (Anderson, 2010).

III Towards a Theorisation of Temporary Urbanisms
We aim in this section to develop the three theoretical strands behind our reinterpretation of temporary urbanisms: we draw initially upon Lefebvre's work to focus on everyday uses and rhythms shaping people and spaces; we then extend evolutionary economic geography and approaches to path creation and path of change to account for the transformation processes led by temporary urbanisms; finally, we turn to scholarship on geographies of architecture to scrutinise the built forms, infrastructures and forms of knowledge associated with diverse forms of temporary urbanisms and their related meanings and materialities. Throughout, we indicate how these theoretical literatures enable us to develop notions of adaptability, activation and trajectory.

Temporary Urbanisms as a Response to Everyday Dynamics and Rhythms
Geographers have offered diverse theorisations of the everyday, often focusing on senses of 'everydayness' in cities . The work of Henri Lefebvre (1991Lefebvre ( , 2004 on the production of the city and the role of differential spaces has already been mobilised in scholarship on temporary urbanisms (Andres, 2013;Lehtovuor and Ruoppila, 2017;Madanipour, 2017) but less towards rhythmanalysis. Our re-conceptualisation of temporary urbanisms rests upon situating its rhythms and dynamics within the multiple forms of everydayness and temporariness in a city -driven by various dynamics, actors and within very diverse configurations and outcomes. For Lefebvre, the production of spaces should 'never be dissociated from an analysis of the production of time, of temporalities that condition the experience of space' (Mendieta, 2008: 153). Temporary urbanisms often reflect Lefebvre's observation: they result from initiatives in diverse urban spaces; the prospect of impermanence constitutes the essence (and, often, attractiveness) of the project while it also directly impacts the social and spatial environment within which it is set up. This thus directly influences how users practice and perceive temporary spaces and how they will progressively change them. In other words, beyond concerns with the duration of any intervention and its impact, temporary urbanisms may intervene into, accompany, or be resisted through, a bewildering array of temporalities and everyday rhythms at any given site, area or both.
Indeed, the very idea of temporary urbanisms implies that processes of activation, adaptability and trajectories of transformations result from urban dynamics and city rhythms, which are diverse, complex as well as context-and casedependent. As Lefebvre (2004: 14) argues: 'everywhere there is interaction between a place, a time and an expenditure of energy, there is rhythm [ . . . ] energy animates, reconnects, renders time and space conflictual'. The concept of rhythms -'movements and differences in repetition, as the interweaving of concrete times' (Simonsen, 2004: 45) -allows us to support our position that the frames and narratives within which cities and urban spaces are usually designed and planned are not sufficiently adaptable to account for emergent and by essence temporary everyday practices. There are few examples to date of large-scale masterplans allowing flexibility in their process to accommodate changes, test various uses and allow greater community engagement (for an exception, see London Borough of Croydon, 2018). If seeking, and many city designers and authorities now do, to promote 'liveable' spaces for both existing and future residents, then they crucially need to attune to rhythms of everyday life in a place -whether embodied actions as diverse as children's play (Christensen et al., 2017) or entrepreneurial inventiveness (Andres, 2011;Bishop, 2015). Moreover, this requires attentiveness to the multiple and diverse rhythms of an urban place, especially in superor hyper-diverse cities: indeed, recent theoretical and empirical work on hyper-diverse cities (e.g. Kraftl et al., 2019) might offer a more detailed toolkit for thinking and investigating the diverse rhythms of city life and hence diverse dynamics of activation.
Turning back specifically to overtly temporary urban interventions, Lefebvre's (2004) notion of rhythmanalysis resonates in part with attempts by (especially 'bottom-up') actors to ensure that temporary urbanisms are attuned to the quotidian rhythms and activities of 'ordinary' -for instance by ensuring that temporary gardens, temporary playgrounds, temporary markets or temporary shops match demands for their use, and are flexible to local/time-specific changes in demand, for example, pop-up museums and exhibitions. They must also, however, reflect the rhythms of life in realms of urban professional practice and policymaking, especially the advent of softer and looser planning frameworks in more 'top-down' examples (Bishop, 2015). As Lefebvre points out in his work on rhythms specifically, and on the production of space more generally, city life is produced through crossings and tensions between the official and unofficial, formal and informal, at different scales, and with their different temporal and organisational logics. This production process resonates with how temporary urbanisms affect the transformation of spaces through various dynamics of transformation: dynamics of acceptance, support, then rejection and conflicts (Groth and Corijn, 2005). In terms of adaptability, then, these are processes that 'valorise places which are quick to construct, relocate and remove, organising space-time to assure its plasticity in the future' (Harris, 2015) or socially engaged spatial practices opening up opportunities in the place-making process (Andres, 2013;Tardiveau and Mallo, 2014).
Thus, at the intersection of these two modalities of activation (broadly, but not mutually exclusively, 'bottom-up' and 'top-down'), the processes of adaptability it rests upon and the trajectories of transformation it triggers involve the co-implication and complication of the different temporal rhythms to which Lefebvre asked rhythmanalysts to become attuned: the cyclical, the linear, the embodied, the sensuous (Lefebvre, 2004). This leads us to a final consideration of the different modes and media through which urban temporalities might be produced -not only through the everyday practices of temporary actors but the exigencies of urban planning and development and hence of the differently manifested rhythms, forces and strategies shaping temporary urbanisms. As specific incarnations of urban rhythms, which are themselves entrained in the specific discursive and practical regimes of trajectories for urban change, it is these modes and media which are constitutive of temporary urbanisms. To address cities' liveabilities, there is a need to juxtapose concurrent, everyday rhythms that constitute and are constituted by these policies and practices -both individually and as they intersect are to be examined. Practically (and politically), this requires greater attentiveness to how some forms of master planning might suffer from a lack of adaptability but have a clear sense of trajectory, while some forms of temporary urbanisms might be adaptable and enable activation but proceed through rhythms that are too informal or precarious to carry along multiple stakeholders (e.g. towards formal consensus).
Lefebvre's considerations of the production of social space and time, of everydayness and rhythms, and how they resonate with our conceptions of activation, adaptability and trajectory, provide a first set of resources for re-theorising temporary urbanisms with a focus on everyday uses and practices. However, to develop and complicate our theorisation of temporary urbanisms thus far, we now turn to the scholarship on paths of creation and path of change, allowing us to emphasise the complex, trajectorial nature of temporary urbanisms.

Transition and Alternative Path Creation and Path of Change
As a key way to advance our discussions of the trajectory of temporary urbanisms, we build in this section upon the recent work on path creation (Binz et al., 2016;Dawley, 2014;MacKinnon et al., 2019) to situate temporary urbanisms as alternative solutions, in contexts of transformation and transition. While the path creation literature is mainly focused on regions, city-level and industry and firms (e.g. Hassink, 2005;Martin, 2010;Martin and Sunley, 2006), there is a rationale to apply it to people, to their (local) formal and informal groupings and to the ways in which they engage with cities and urban transformations. This may enable the capturing of the evolutionary processes of temporary urbanisms -their trajectories -and their impacts on people's lives, hence liveability.
This stresses the importance of places and specifically 'place-specific legacies and conditions [that] play a critical role in fostering new path creation' (Isaksen, 2015). Temporary urbanisms are a response to everyday needs not being fulfilled: citizens/residents can thus either accept the environment that they live within or, if the opportunity arises, they can try to engage in temporary urban activities so that their lives become less constrained by the path dependency within which they live. For example, children can make use of an unused construction site and transform it into a temporary playground and BMX track . Temporary urbanisms provide an opportunity for individuals to shape different outcomes, connected to their own lives, but with impacts on the future of an area, however dependent on paths that more powerfully pattern their lives and environments (for instance, in the example of the construction site, the eventual decision to build houses there).
As noted by Andres et al. (2019: 4), 'temporary urbanisms are the outcome of processes and practices contributing to spatial and social adaptability, allowing places to be purposely used and activated responding to specific economic and social needs'. Such understanding demonstrates that temporary urbanisms reflect 'evolution rather than permanence' (Andres et al., 2019: 4), which feeds into our interpretation of both adaptability and trajectory. This evolution, from one path -'the unused' -to another path -'the temporary', is contextualised and pathdependent: decisions made in the past limit current choices and thus favour some paths of others. This explains why some spaces remain unused but also constrains what forms of temporary urbanisms can occur and who can lead them.
Activation processes through temporary urbanisms are localised and can be embedded -or not -within other paths of change. As such, they may occur irrespective of other forms of path dependency, in other words independently, or being connected to other paths of creation. This is often a site and a building on its own or within a wider area of regeneration/development not following the same path of transformation, for example, temporary outdoor facilities (football pitch, swimming ponds) within largescale regeneration schemes set up to respond and serve local communities while bringing a creative touch to an often long, sometimes conflicted, process of transformation. Typically, a place in a city may have different layers following different forms of path dependency and creation. This highlights diversity and variety with such temporary uses being seen as a local initiative targeting people's lives, a marking/ branding tool or a way to leverage attraction and impact land values. In our example of temporary uses within large-scale regeneration schemes and as in most top-down initiatives, temporary urbanisms are layered over existing path-dependent outcomes and are swept away as path-dependent outcomes are reinstated. Even when temporary urbanism is bottom-up and linked to a downturn in the property markets leading a range of options for temporary projects, once the latest start to shift, temporary opportunities are reduced and removed progressively often leading to gentrification (this has been well documented in Berlin -see Colomb, 2012). The path creation process of temporary urbanisms (with a temporary element that can last several months to several years) is thus characterised by significant diversity within the material and immaterial changes and forms of activation and adaptability it implies to a place and its surrounding environment (thus also connecting with our discussion of 'rhythms' and their trajectories, above), particularly towards land value capture (Bryson, 1997;Loo et al., 2018) but not solely.
Scale and size matter here. The nature and diversity of temporary urbanisms mean that material transformations of a space are first bordered within a specific place; however, the path creation process which then occurs spreads beyond the place and can lead to different scales and trajectories of transformation; those are dependent of preconditions inherent to the setting and context, that is, dynamics or forces in place including actors involved, planning policies and development strategies attributed to the site. Typically, a temporary community garden will follow a very distinct path (from either being sustained or taken out, often via considerable conflicts) from a mixed-uses temporary container-based project (which may lead to the gentrification of an area). In these illustrations, the path creation process is path-dependent on how and why those temporary uses were set up and within what type of path of change for their wider setting area, if any.
This diversity of trajectories rests upon the path creation process of temporary initiatives and how such processes 'un-lock' (Martin and Sunley, 2006) different paths of change and lead to the involvement of various parties, leading to distinct outcomes, which can result in conflicts, or not. This unfold directs attention to the new paths generated, reflecting the idea of 'path as process' (Martin and Sunley, 2006). Temporary urbanisms, in any form, offer opportunities for change. In some cases, but very rarely (e.g. for temporary reuse of empty units/shops), no path of transformation occurs; the temporary use ends and the space remains empty. In most cases, however, and whatever the setting up of the temporary initiative is, temporary urbanisms offer possibilities for a new path to emerge in a place or on a plot, which can be smooth or conflicted. This new path may be temporary and embedded within very specific and timeframed goals (as in large-scale regeneration schemes), or it might shape what emerges in that place/plot for a longer period of time (our temporary playground example). In other words, temporary urbanisms generate path creation processes, opening up possibilities for alternative uses with different outcomes; those outcomes can either be through pre-planned transformation, where the path creation process nurtures a wider path creation process built upon large-scale regeneration and land value capture, or it can be more incremental, driven by residents and citizens, who by taking ownership and leading the path creation process unlock alternative scenarios and then ensure their needs and visions are accounted for (which often can lead to conflicts).
This leads us to our final point of how processes of activation, adaptability and the trajectory of change of temporary urbanisms sit within a wider system of thinking about urban transformations. As noted by MacKinnon et al. (2019: 5), '[p]ath creation occurs through a process of "bricolage" involving a multiplicity of actors who enable the alignment of heterogeneous actors, institutions and networks' (Boschma et al., 2017;Carvalho and Vale, 2018;Garud and Karnøe, 2001). Bricolage here is a subset of adaptability and reflects how actors engage in transforming a site in a nonpermanent and hence flexible way. In essence, temporary urbanisms go against the culture of the planned and the finished; their more recent, formal deployment reflects how developers, local authorities and planners have been changing their approach to the impermanent, accepting that more adaptability in the urban process generates positive changes rather than complicates the transformation process. Those are institutional changes in the cultures of producing cities and spaces within cities, which rely of highly localised and contextualised thinking as well -as we argue in the next section -on the circulation of knowledges about temporary forms of planning, design and architectural practice. Any temporary urban intervention constitutes one or more alternative dispositions to the future (Anderson, 2010) -of how the pathways of any urban space might be created thanks to alternative and adaptable solutions. These processes of adaptability are often similar to bricolage mechanisms, as they involve experimentation, testing pathways, built (in part) upon everyday needs but also the trajectories of different professionalised actors and organisations. The creative process here is important and this explains why architects and urban designers have often been at the forefront of some of the most well-known temporary projects, such as recently the (highly criticised though) PLACE/Ladywell in London, by Rogers Stirk Harbour, a temporary housing development project combined with commercial units on the ground floor advertised as a catalyst for future regeneration or more than 20 years ago, the transformation of former tobacco factory in Marseille into a flagship cultural project (Friche de la Belle de Mai), supported by the architect Jean Nouvel.
Building on the previous section on everydayness and rhythms, using the path creation debate allows us to re-interrogate the roles of the agents of change who are not (or are not only) the traditional actors of place-making (e.g. see Andres, 2013;Groth and Corijn, 2005) and how they mobilise processes of bricolage to emphasise change and hence adaptability. A re-theorisation of temporary urbanism needs to have an expanded notion of who are the (potential) agents of change, what forms of bricolage they adopt, as well as being cognisant of the power relations between them. Such agents can include local communities and economic or cultural entrepreneurs -individuals and groups who do not necessarily hold official decision-making power nor (usually) the professional recognition to shape places (as professionally accredited planners or architects would), but also developers who have embraced and understood the benefits of temporary urbanisms for land value capture. We now develop and frame this discussion by turning to the importance of the built environment in scholarship on the geographies of architecture.

Geographies of Architecture: Meaning, Materiality and Knowledges in/of the (Temporary) Built Environment
Given the involvement of architects in (particularly experimental) forms of temporary urban intervention, there is considerable scope to fold a long line of geographical work on architecture into theorisations of temporary urbanisms. A key starting point, which builds on the previous section, is that geographers of architecture have held a long-standing interest in how built forms come to symbolise particular political, social and/or cultural values (e.g. Domosh, 1989;Goss, 1993). Moreover, those meanings are criss-crossed, juxtaposed, enlivened and/or resisted by the everyday, embodied practices that go into the creation, maintenance and use of a building -an analysis of which Lees (2001) termed 'critical' geographies of architecture (also Kraftl, 2009Kraftl, , 2010Sarmiento, 2018). These approaches may be specifically useful for thinking through how notions of activation, adaptability and trajectory might be theorised and studied in temporary urban contexts -especially when thinking about their material and infrastructural characteristics. Recently, for instance, Kraftl (2014) assesses both larger and smaller scaled forms of biopower at masterplanned, 'sustainable' communities in the UK. On one hand, he examines how policymakers, planners and architects sought to govern every aspect of life in communities -from stipulations about how 'sociability' could be fostered through urban and architectural design to the relative porosity of pavement surfaces. On the other, he demonstrates how the community responded through their own acts of meaningmaking (naming emergent features of the property) and resistance (questioning the intentions of developers and policymakers). Thus, building on the two previous areas of scholarship, so-called 'critical' geographies of architecture could afford nuanced theories and methodologies for critically assessing and juxtaposing the different 'architectural movements' that constitute built forms (Kraftl, 2010: 327). Those movements may be discursive, affective, embodied, imaginative -and/or far more besides, and require a full range of methodologies to witness them. What is important here is a consideration not only of the everyday and socio-economic contexts of temporary urbanisms but of how these are recursively entwined with the materialities of attempts at place-making (i.e. of activation). Hence, 'critical' geographies of architecture could offer a set of tools for further refining a theory of temporary urbanismsparticularly (but not only) in the key areas indicated below.
Firstly, 'critical' geographies of architecture illuminate not only the rhythms through which temporary built forms come to be but the ways in which built spaces come to be valued, contested and felt (den Besten et al., 2011;Kullman, 2019) by the 'agents of change'. Such scholarship therefore offers a further set of nuanced strategies and languages for mapping and questioning (from a new vantage point) several of the issues raised above: the precise choreographies of everyday life, through ethnographic observations, vignettes and visual methods (Kraftl, 2010;Lees, 2001); the ways in which particular spaces come to be viewed as 'vacant' given their histories; and the ways in which future trajectories -and their representation or materialisation as sketches, models or experiments -can be 'read' in terms of the ideals they embody (e.g. Bunnell, 1999). In turn, all of these processes are intimately bound up with, and productive of, the adaptability of a place, as constituted through symbolism, materiality, emotion, memory and embodied practice.
Secondly, geographers of architecture have given greater attention to the material stuff of buildings, and these approaches could be applied to thinking through the materialities of temporary urban interventions (and especially the role of architectural practices, e.g. Jacobs, 2006;Moran et al., 2016). Drawing on Science and Technology Studies (STS) and Actor-Network Theories (ANTs) (among other approaches), two preoccupations of this work are pertinent to theorising temporary urbanisms. On one hand, we would call for critical scholarship on temporary urbanism to pay greater attention to the materialities of temporary urban interventions, linked to what is seen and perceived as acceptable (including building regulations and safety standards). Whether deploying the languages of STS, ANTs or other styles of material thinking, the capacities of materials are often absolutely central to the activation and trajectory of temporary interventions. For example, the use of containers has been a world widely used tool to design temporary structures, for mixed used, housing or cultural facilities projects. It is of course rather obvious to point out that the properties of materials matter to architectural or urban design practice; but in the case of temporary urbanisms, it could be argued that materials require particular properties -flexibility, cheapness, lightness perhaps. These properties may be site-specific but will likely too be bound up in the ideals and aspirations that structure any site.
On the other hand, and thirdly, the 'material turn' in geographies of architecture has enabled close analyses of the circulation of building designs and, particularly, technologies (see Jacobs et al., 2007). To this we could add recent work about the circulation of (architectural) knowledges, often at a global scale (Faulconbridge, 2010(Faulconbridge, , 2013 but also locally. Clearly, these kinds of circulation might be considered as trajectories and efforts to more clearly map the multiply-scaled trajectories of knowledges about temporary urbanisms would be welcome. However, in a more critical sense, as we have begun to argue throughout this article, temporary urbanisms are characterised by particular forms of 'technology' -both in material and infrastructural terms and in terms of the positioning of such interventions with, in and as formal planning processes, design practices and injunctions to creativity (i.e. in terms of path creation). Thus, drawing inspiration from diverse work on the circulation of architectural knowledges and technologies, temporary urban scholarship might grapple with a series of questions. How do temporary urbanisms circulate locally, nationally and internationally, and how in turn are they activated by diverse actors, whether 'local' or not, 'professional' or not (thus anticipating the need to broaden notions of 'activation' beyond individual sites, towards more comparative studies)? How do specific genres, styles or ideals surrounding temporary interventions come to be seen as 'exemplars', and how, when they circulate, do they 'land', locally (thus again presaging the need for more comparative studies of adaptability)? Going back to our reference to the temporary use of containers, such forms of modular architecture match the physical needs of the projects as well as their overall image and hence ambience which explains why they have become such a popular exemplar design which has travelled internationally; the container, as an architectural form, is a synonym of flexibility and adaptability (from its original use). Technically, such construction methods can be easily assembled and dissembled and have been very frequently used for residential and commercial buildings (Hong, 2017). Thus, the perceptioncirculating globally in architectural and other knowledges -of containers being mobile, and hence adaptable, explains its wide use and valorisation, despite, in practice, very high maintenance costs. Moreover, the example of containers points more broadly to how an attention to the symbolic, visual and material properties of a temporary urban interventionwhether considered 'architecture' or notcould, through the conceptual languages of the geographies of architecture, extend notions of activation and adaptability.
Finally, very recent work on architectural practice has turned the lens back onto architecture as a profession -both in terms of analysing how architects work and in terms of exploring how geographers might actually collaborate with architects in the production of knowledges about space and its inherent dynamism (e.g. Jacobs and Merriman, 2011). There is plenty of scope to critically consider how such practices are inveigled in, and constitute, processes of activation, adaptability and trajectory. Lorne's (2017) provocative exposition of architectural (non-)practice could offer a key touchstone for this element of a theory of temporary urbanisms. Lorne examines instances where architects may contribute their professional expertise about the creation of spaces without actually building much (if anything). Significantly, Lorne focuses on instances of architects' 'spatial agency' where a building is not necessarily needed -'co-housing and ecological community garden projects through to protest movements and ad hoc urban interventions' (Lorne, 2017: 276, emphasis added). 'Spatial agency' denotes forms of 'spatial judgement, mutual knowledge and critical awareness' (Awan et al., 2013: 33) that draw on an architect's expertise but do not necessarily lead to formal architectural plans or forms. As Lorne suggests, ad hoc -or temporary -forms of experimentation could well form key examples of such forms of spatial agency. Lorne's analysis is particularly helpful for theorising temporary urbanisms because it offers a framework for combining attention to materialities, practices and (politicised) ideals and values. It is particularly relevant here since temporary urban interventions may not actually necessitate the building of a building (if anything (much) -as per the example of transport containers, above). This, then, casts an additional and perhaps provocative (or, at least, counter-intuitive) light on notions of path creation -where that path may not lead to the building of anything at all, and where trajectories of change may involve not making activations or adaptations as well as doing so.
In this section, we have argued that a long line of work on the geographies of architecture might offer important sets of resources for analysing the symbolism, values, ideals, practices, emotions and materialities that constitute the (non-)design of temporary urban interventions.
Building on the two previous sections, they offer ways to systematically analyse how activation, adaptability and trajectory are, in reality, often co-implicated -in particular, by questioning the role of architects and other design professionals in relation to other stakeholders. They also offer more specific, nuanced methodologies for tracing the rhythms and paths of change through which temporary interventions are -however tentatively -concretised in situ.

IV Conclusion
Our (re-)theorisation of temporary urbanisms has extended beyond questions of temporality and duration in order to explicate how temporary urbanisms can be elevated as a new shared concept among a range of urban-related disciplines. The article has sought to elevate three key concepts -activation, adaptability and trajectory -which emerged as key analytical concerns in our own research drawing upon the diverse literature in the field.
We highlighted the significance of rhythms in Lefebvrian conceptualisations of the everyday, enabling a critical (re-)interrogation of the diverse 'top-down' and 'bottom-up' actors and processes involved in developing and contesting urban temporariness. We then focused on the mechanisms of transformation and the role of agents of change, layering a discussion of concepts of path creation, dependency and change. We argued that the path induced by the temporariness process can help us understand the processes and layers of transformation underpinned by various forms of temporary urbanisms. This allowed us to highlight what are the different trajectories of temporary urbanisms, and dependent on how those have been constructed and embedded within a wider vision, involvement of different actors is different and so are the outcomes for the different parties involved, leading of course to potential conflict of trajectories. Finally, we wove in a discussion of geographical work on architecture that can provide a toolkit for more detailed exposition of the processes of signification, embodied practice and feeling, materiality and knowledge circulation through which the rhythms and values of temporary urban interventions are (or, crucially, are not) instantiated. This new approach has allowed for a more systematic (but of course not universal) theorisation of temporary urbanisms that may afford a framework for analysing and comparing how, for instance, dynamics of the everyday and of professional practice are clearly acknowledged in triggering creative urban reconstruction.
Drawing upon those concluding thoughts, and in order to continue explicating the diversity of temporary urbanisms, our broader theorisation of temporary urbanisms offers a starting point for more systematically theorising and comparing often disparate studies of interventions into urban spaces. Our threefold language of adaptability, trajectory and activity, opens out opportunities for several future avenues of research, which can help articulate a more systemic approach to understanding cities and the reproduction of urban spaces, fostering greater dialogues among not only disciplines but also agents of change. More work is thus required in comparing diverse forms of temporary urbanisms as both highly contextualised and localised, but where knowledges and practices also circulate locally, nationally and internationally; again, the threefold conceptual language outlined in this article could offer a framework for such comparisons.

Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/ or publication of this article: The authors gratefully acknowledge the support of the UK Economic and Social Research Council for a portion of the research on which this paper is based. The ESRC support the project 'New Urbanisms, New Citizens: Children and Young People's Everyday Life and Participation in Sustainable Communities' (grant reference RES-062-23-1549).