Pavements Of Pleasure Ana Luz


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Walking Choreographies, Visual Illusions And Emotional Landscapes Of Waiting

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Pavements Of Pleasure Ana Luz

  1. 1. Pavements of Pleasure: Walking choreographies, visual illusions and emotional landscapes of waiting Ana Luz, The Bartlett School of Architecture, University College London, UK Abstract Pavements are the most banal and ubiquitous form of the urban fabric. Literally outside the typologies of street furniture and soft landscape design, pavements (sidewalks or footpaths) are crudely defined as the artificially covered and raised walk surfaces for pedestrians at the side of the road. However, as the foremost physical platform of support for locomotion, and thus a connecting element of mapping between body and landscape, pavements could be considered as experiential constructions of urban exploration. For the urban nomad, here suggested as co- producer with the place-maker, pavements can be the canvas for the city everyday rituals and narratives, the stage for emotional topographies. Using the site-specific traditional mosaic systems of the Portuguese sidewalks as reference, this paper will discuss the possibility of a walking notation for urban pavements. Three diverse but linked conceptual frameworks will be considered: 1. conceptions of aesthetics of mobility and of disappearance; 2. principles of optical art, anamorphosis and visual illusions; and 3. theories of playability and pleasure. It will be argued that pavements can deepen the poetics of any given place, in particular the uninspiring spaces of mobility and travel like transport nodes, where spatial practices such as walking and waiting are embodied by the tempo of empty and negative times of boredom. Keywords Pavements; Portuguese sidewalks; walking choreographies; visual illusions; playability. Introduction Within environmental design disciplines, hard landscape design usually refers to the built work of paving design, landscape enclosures and landscape/street furniture (Lisney and Fieldhouse, 1990). Fundamental to hard landscape design is the principle of construction (techniques and materials), and also the functional detailing of spaces between buildings where pedestrian movement occurs. This means that the formal and technical qualities of urban settings are utterly related to human scale, activities and movement. This is certainly the case of paving design and ground surface forms, which are typically associated with transport or road infrastructures and pathways’ maintenance (repairs, resurfacing and cleaning) but are in fact one of the most important landscape expressions. Spatially speaking, pavements refer to all the durable surfaces of an area intended to sustain either vehicular or pedestrian traffic. These paving forms are generally connected with the lateral areas of ground on either side of a roadway. More common in modern urban areas, pavements are also defined as sidewalks or pathways, which are (foot)paths designed for or by pedestrians (i.e. unexpected trails). Artificially covered with concrete, tarmac, asphalt, brick, stone or even wood, pavements are constructed as raised walk surfaces that run alongside a thoroughfare (street, way, road). Perhaps due to their prosaic flat quality, they are usually not considered as part of urban furniture typologies (e.g. sitting, lighting, information, planting, enclosing and sanitary fittings). 1
  2. 2. However, as the foremost physical platform for locomotion, pavements are an integral part of every urban fabric and one of the key elements of support of people’s basic modes of travel and movement – i.e. walking and way-finding. Following Tim Ingold’s (2004) proposition of a “culture on the ground”, this paper discusses a more grounded approach to human movement, landscape design, and embodied skills of pedestrian engagement and way-finding perception. Often taken for granted, pavements are more than just the standard finishing of interior floorscapes or outdoor patchy groundscapes. Programmatically, the physical ground of urban landscapes is normally entrusted only with service functions (circulation, access, sometimes parking or storage, etc.). All the same, in a rather poetic way, the ground pavement can be considered as the stage of everyday life practices and a valuable built-environment instrument in which to design more emotional topographies (engaging sceneries, playful settings, and expressive features). In this sense, it is argued that the science and art of paving forms reveals two important conceptions regarding the human-environment relationship: firstly, pavements are the connecting points or interstitial layers between body and landscape; and secondly, they function and are experienced as mapping constructions in people’s urban explorations. These two conceptions suggest that pavements might then deepen the poetics of any given place or particular urban experience. This can be the case of the frequently disjointed, monotonous and grey spaces of travel such as stations, terminals and gateways; and especially, if to inhabit these landscapes of mobility implies frustrating way-finding experiences and the empty and negative times of boredom and waiting. By considering exploratory work done outside the liminal scenario of a suburban train station, this paper proposes the use of pavements as canvas for urban design. For this purpose, the work draws on two important spatial systems: the site-specific traditional mosaic systems of the Portuguese sidewalks as illustrative reference; and, the typographical schemes of notation systems (e.g. dance, movement and music notations) as basis for a walking or way-finding notation at spaces of travel. Portuguese sidewalks The Portuguese sidewalks – Calçada Portuguesa – are marked by a simplified and suggestive technique of black and white visual game of stone paving tessellation (black and white small cube forms of calcareous, basalt and granite). This traditional paving art is used in most pedestrian areas in Portugal, and it is usually found in almost every city sidewalks and urban plazas. The art of paving is believed to have originated in Mesopotamia, where rocky materials were used to cover the interior and exterior surfaces of constructions. Later adopted by Ancient Greek and Roman civilizations, paving crafts were largely developed by the latter that used to pave all their empire’s vias using the rocky materials of their surroundings. Introducing particular techniques of foundation and surfacing still employed today in the Portuguese calçada, the Romans also applied the paving methods to their building interiors. Here art forms such as the tessella (tessera) or mosaic configurations were extensively used as remarkable decoration elements and also as an expressive illustration of everyday reality and ways of living (Matos, 2004). Later, the Arabic inheritance brought some substantial changes to the organizational and structural shape of the public pavements, when techniques of draining and empting were developed to the complex crop systems of dams and waterways. Consequently, the drawing of both the decoration (the arabesc) and the construction preservation of pavements assumed a more public character, spreading the interior decoration to the streets and giving more visibility to the paving craft as representation of political, religious and art activities. In Portugal, the traditional art of paving was further developed after the Renaissance; especially after a series of significant earthquakes in the 16th and 18th centuries (e.g. Lisbon, 1751). As a 2
  3. 3. result, cities’ reconstruction would greatly advance urban planning and the modernization of traditional medieval streets (Matos, 2004). In terms of urbanistic development and accessibility, sidewalks began to be planned together with the adjacent architecture. Several important buildings and urban squares in Lisbon (e.g. Rossio and Figueira Squares, Restauradores and Liberdade Avenues) were amongst the first urban spaces and public walkways to be fully covered with large tapestries of stone of black and white drawings. Following roman techniques of mosaic (i.e. bedding and setting of stones), the artistic paving activity was performed throughout the whole country and overseas’ colonies (e.g. Brazil) by hundreds of calceteiros craftsmen (pavers), who were in charge of the construction of new streets’ pavements, novel techniques for tessellations, tile patterns and aesthetic compositions. Particular motifs such as the “wide sea”, the “interwoven ropes”, the Portuguese Discoveries’ caravels and numerous representations of daily practices, became symbols of Portuguese culture and part of a pictorial language impressed upon the ground (Bairrada, 1985). Traditional pavements soon became a mean of communication which told the history of the place and the everyday narratives of its users, also promoting the pedestrian pleasure of ‘going for a walk’ (passeio público). Artists and writers alike who lived and walked through these stoned engravings literally praised the poetry of pavements’ chromatic games, the skill process of laying stones and the embodied feelings of such painted topographies (Cabrera et al., 1990; Matos, 2004). Figure 1 – Portuguese sidewalks: pavers, pavements and patterns Unfortunately, the art of paving slowly became restricted to conservation works in historical areas or important top architectural projects. This was due to factors such as: the high cost and reduced robustness of traditional paving (in comparison to concrete-based or bituminous materials); the craftsmen’s arduous labor of laying stone by stone while squatting down; the scarcity of material resources; the municipalities’ low budget; and also the present ‘barrier-free’ regulations for street accessibility. However, despite economical and manufacture limitations pavements have recently become a source of inspiration as aesthetic expression for several artists, who transferred the color, techniques and mosaic composition to both the inside of architecture surfaces (e.g. Chiado) and the exterior road surfaces of vast new urban interventions (e.g. the urban area of Parque Expo, former Lisbon Park Expo’ 98). Although now subject to fewer applications or technological adaptations, Portuguese pavements continue to be a strong cultural manifestation. The memory, culture and urban landscapes of Portuguese identity will be forever immortalized in the artistic stoned pavements of the sidewalks (Bairrada, 1985; Cabrera et al. 1990; Matos, 2004). 3
  4. 4. Walking choreographies In their recent work Groundscapes, the architectural team Textbild proposes: “analogous to a plan stretched out on a drafting table, the ground is programmed as canvas of a picture that can be grasped as a whole […] to organize space” (Ruby and Ruby, 2006). Extending the architectural drawing into the horizontal surfaces of the ground, the authors suggest the conception of “inscribed ground”. The inscription of an image into the ground transforms the lines, points and surfaces of a simple drawing into a topographical relief with several urban structures and programmatic elements, which users in turn tend to “experience haptically, crawling like ants across its surface while attempting to grasp its meaning through touch” (Ruby and Ruby, 2006). This ‘touch’ refers not just to the sensory ability of hand tactility, but to an embodied experience of pedestrian movement, thus including the visual, auditory and locomotion body perception. Challenging the “groundlessness of modern metropolitan dwelling”, Ingold argues for a more grounded approach to spatial perception, in which pedestrian experiences and walking activities should not be reduced to short intervals between other vehicular movements and to which feet are considered as mere “stepping-machines” (Ingold 2004). By proposing a balance of the senses as an alternative to the typical visual and manual modalities, Ingold suggests restoring the haptic and kinesthetic sensations of touch through the feet (albeit mediated by footwear), which are literally people’s foremost continuous points of contact with their surroundings. Hearing with the feet, observing through a continuous itinerary of movement or feeling the ground through the whole body are just some of the challenges that a new pedestrian touch may reveal. Undoubtedly that the study of pedestrian behaviors, spatial navigation processes and “walkability factors index” (Stonor et al., 2002) are crucial for forecasting pedestrian flows and modeling pedestrian movement in light of changes in urban configurations. However, one is more interested in the ‘intangible notation’ defined by everyday walking choreographies (i.e. steps arrangements, sequences and directions; movement routines and designs; feet pressure and intensity; way-finding dances and pauses). A walking choreography happens, for instance, within everyday practices of coming and going in- and-out spaces of travel like train stations. Here, pedestrian operations such as lingering, stopping or temporarily pausing, occasional standing, fidgeting, stalling ‘time’ and disconcerted walking often occur. These practices define, one argues, the contemporary emotional landscapes of waiting. As with fingerprints, pedestrians’ density, cross-currents and feet pressure ‘leave behind a trace’ of feetprints and motion uses that subliminally are impressed on to the groundscape. Hypothetically, if pavements could then act as ‘living organisms’ and capture, react or change according to these ground imprints, a walking notation or a way-finding system of pedestrian touch could be bodily sketched. A pavement walking notation is like stepping or drawing on sand; or creating endless ephemeral stencils that overlay each other; or even gently pressing electroluminescence conductive materials that change color or pattern with pressure touch and temperature. Since walking involves motion perception, a temporary notated language as such could follow some of the principles of dance, music and movement notations. Hence, comparable to Portuguese sidewalk typologies, its graphical representations would become the motifs of the pavement drawings and ever-changing patterns. Aesthetics of disappearance and of mobility This time-based body impact of motion perception and the pedestrian process of (de)codification (walking notation) are to some extent analogous to Paul Virilio’s notion of “aesthetic of disappearance” (Virilio, 1991). This refers to both the experience of change under speed (e.g. watching the landscape quickly ‘passing by’ through a train window) and to its insubstantial or fleeting visual representation. This ‘dematerialization’ of the visible was explored, for instance, in kinetic art where the disappearing movement was registered through a series of momentary 4
  5. 5. postures and ‘freeze-frames’, introducing contemporary explorations of ‘trace forms’ in dance notation. Although originating in the arts, the aesthetic of disappearance is an interesting design strategy for the ground level of landscapes of waiting, where the deliberate organization of a way- finding path and the topography around it may turn motion perception into an aesthetic experience. Depending on walking and waiting time intervals and durations, objects and terrains can be experienced as multi-sensory perceptual artifacts, varying in the degree of focus (e.g. details such as pavement textures fading or changing with pedestrian movement) and meaning. Similar to this aesthetic of disappearance, Ossi Naukkarinen proposes a ‘moving field’ of aesthetic mobility (Naukkarinen, 2005). This refers to the aesthetic and/or artistic aspects of mobility and change, which relate people’s ways of moving with aesthetic approaches and choices. He states: “our everyday mobility consists of various ways of getting about, and sometimes our approach to them is aesthetically colored: we pay attention to how beautiful, ugly, fascinating or enthralling a walk, a drive, or a route is”. Naukkarinen suggests that these ‘sensuous’ and structured acts of moving about offer intense kinetic, visual and auditory experiences, which imply that mobile activities can often be considered as aesthetically rich phenomena. Beyond the primary purpose of moving (i.e. to get somewhere else), the search for aesthetics experiences and environments is often one of the reasons for travel. However, arguing against the contemporary mindset obsessed with speed, mobility and efficiency, it is also important to consider the notions of ‘temporary occupancy’ and ‘momentary stillness’. Ultimately, the final purpose of walking or moving is to stop. While traveling, and in particular before and after a journey, there are usually occasions of interruption, pauses between moments of mobility. Those are normally the first moments of encounter with the space traveled from and to. For instance, at train stations when leaving the train to encounter the city ahead or vice-versa. This means that a mobile aesthetics, an aesthetic of mobility or even of disappearance, are also defined by a waiting discontinuity. Both bodily motion and stillness help to determine people’s perception and appropriation of environmental features – i.e. the ‘appearance’ of the world (Ingold, 2004). Certainly, there is a difference between moving about by oneself and observing movement or mobility from a standpoint, either standing still outside or moving inside a vehicular capsule (Naukkarinen, 2005). These mobile variances shift pedestrians’ aesthetic valuations as the experience of sensory perception unfolds and changes through these diverse choreographies. What is interesting here is that the pedestrian, mobile or at rest, participates in the construction of its surroundings through multiple paths of observation, motion and emotion (Ingold, 2004). While on foot, with strides and pauses, a walking choreography is the primary act of ‘transformation’ of the territory/landscape. As Francesco Careri proposes, walking is an “aesthetic practice”, but also an “aesthetic instrument of knowledge” (Careri, 2002). Ingold supports this interrelated notion between aesthetic perception, cognition and locomotion, by suggesting that “walking [is] a form of circumambulatory knowing” and that people know as they go, not before they go (Ingold, 2004). These conceptions focus on the embodied process of moving per se and its transitory and transformational states, rather than on the contemporary modality of vehicular mobility. In this context, one argues that the experience of pedestrian touch is not just marked by the modern nomadic lifestyle of accelerated mobility, constantly being ‘on-the-move’ or ‘in transit’; but, is instead defined by the pedestrian ‘slow-motion’ rhythms of everyday life, by the ‘stop-motion animations’ that happen in between. Animating anamorphic topographies and visual illusions Following Ingold’s proposition that perception is a function of movement, it is possible to infer that what people perceive in their surroundings depends on how they move through them. This simple conjecture can provide paving design some directions and allusions. A walking choreography 5
  6. 6. through a landscape [of waiting or not] is informed by a sequence of distances and projections (e.g. images in perspective, sounds in distance), which people construct as they go based on their sensory perception or pedestrian touch. Contrarily to graphical perspective, this motion through paths and ‘lines of sight’ implies multi-focal and multi-direction connections. In theory, this ‘cubist’ construction of circumambulatory knowing would (arguably) provoke ‘momentary distortions’ similar to that of a kaleidoscope or mirrors’ room; but, in reality these multi-focal juxtapositions rarely occur. Nevertheless, one could ask: what if a distortion of a sensory perception could be captured within the surroundings; what if pavement landscapes could be squeezed and stretched in sensory illusions as if through anamorphic lenses? There are several types of sensory perception distortions (e.g. optical, auditory, touch illusions), which are ‘misinterpretations’ of a true sensation perceived in a distorted manner. Each of the human senses can be ‘deceived’ by illusions, but visual phenomena and optical trickery are the most well know. Optical or visual illusions exploit errors of perception (phenomena of illusions) or assumptions made by the human visual system (usually their basis is in the visual pathway and not in the optics of the eye), into incorrectly perceiving what is present or perceiving something that is not present at all (Coren and Girgus, 1978). There are physiological illusions that occur naturally (e.g. afterimages and perceptual aftereffects), and cognitive illusions that are caused by a misapplication of perceptual knowledge to interpret or read sensory signals (Gregory, 1997). Cognitive illusions are commonly divided into: ambiguities, or ambiguous illusions, which are pictures or objects that elicit a perceptual change between the alternative interpretations (e.g. the figure-ground Rubin vase); distortions, or distorting illusions, which are characterized by distortions of size, length or curvature (e.g. the Mueller-Lyer ingoing and outgoing arrow-heads illusion); paradoxes, or paradox illusions, that are generated by paradoxical or impossible objects (e.g. the Penrose triangle); and fictions, or fictional illusions that are defined as the imaginary perception of objects by a single observer such as delusions and hallucinations (Coren and Girgus, 1978; Gregory, 1997; Wade, 1990). Inspired by the optical characteristics of the eye and the laws of visual perception, optical illusions were adopted, explored and manipulated by the 1960s artistic movement Op Art. Through hard- edge and abstract compositions Optical artists explored the arrangement of serial structures and geometrical forms or patterns to create striking visual effects of movement and vibration, with impressions of flashing, swelling or warping and hidden images (Wade, 1982). By sharing academic theory about the relationships between body, time, space and movement, Optical art was developed in parallel with Kinetic art in the 1960s and 70s, which underlying principles of chance and randomness are based on real or illusory, mechanical or random sequences of movements. Also exploring mathematical and physical rules of perspective and visual perception, there are anamorphoses or anamorphisms. These are unconventional perspectives or unintelligible distortions of elongated or swirled smears of shapes and lines that only reassemble themselves as a coherent image when viewed from a particular extreme angle, or in a convex or trapezoid mirror (Baltrusaitis, 1977; Warner, 2004). Since the Renaissance, the geometrical technique of unconventional perspective through anamorphosis has been largely explored in painting and printmaking, which designs are based on visual compositions of deformed, doubled or hidden/secret images (Leeman et al, 1976). A particularly well-known example is the oblique anamorphosis of a skeleton distorted image in the painting The Ambassadors by Hans Holbein, 1533. In anamorphic art, the images do not make sense unless the viewer knows how or where to place the ‘eye’ or move either the image or himself around it. To some extent, that is the case of the ‘anamorphic’ designs of road markings. In order to be viewed by road users from moving and shallow angle positions, some road markings vary the vertical dimension of the lettering (e.g. stretching technique), exploring the apparent shrinking effect (foreshortening effect) of visual perception when the observer is moving at speed. 6
  7. 7. A common element present in all these perceptual illusions and visual allusions is the ‘distortion of reality’ or ‘changing perspective’, either graphically represented or physically embodied by the observer’s movement. By exploring this element of embodied movement, it is argued that the design of paving landscapes can ‘play’ with sensory perception illusions as to create physical anamorphic topographies. The following images show some proposals for paving design and mock- up explorations of flat and 3D anamorphic constructions, which use ‘weaving’ techniques and optical, auditory and touch illusions as design techniques for the pavements way-finding playability. Figure 2 – Design explorations: weaving pavements and anamorphic topographies Playability and pleasure This paper argues that playability can be explored as design criteria, fostering imagination, immersion and enjoyment. As a theoretical concept, playability is difficult to define since it comprises a wide range of practices of learning, leisure and free-time. Usually, it refers to ‘non- serious’ activities of recreation and enjoyment, or any other entertainment activities that act as work antithesis. More frequently, playability is associated to the degree and quality of an activity that is structured and goal-oriented such as ‘to play a game’. However, in lay terms, the concepts of play and playability are intrinsically related to experiences of ‘having fun’ and thriving on satisfaction achievements – also known as gratifying playful pleasures. The notion of pleasure was greatly explored by the anthropologist Lionel Tiger (1992), who defined not a universal explanation for the concept but rather a framework of four interrelated types of pleasure. Firstly, there are the physio-pleasures, which are related to the body and the senses, deriving from the sensory receptors and including feelings of sensual and sexual pleasure. Secondly, there are the socio-pleasures, which are associated with inter-personal and social relationships, deriving from the enjoyment of being in the company of others – social interactions and social identity. Thirdly, the psycho-pleasures are linked to the mind and derive from the satisfaction and fulfillment of accomplishing a task. And finally, the ideo-pleasures which are related to emotions and values, deriving from the appreciation of ‘abstract’ entities (e.g. art or music), and also associated with the aesthetic principles of objects and settings’ environmental perception (e.g. balance, harmony, complexity, and other Gestalt principles of organization). 7
  8. 8. The difficulty of generally defining what is and what constitutes ‘pleasure’ is due to the fact that pleasures are so idiosyncratic, private and immeasurable; but, it is also this indeterminacy what makes it so powerful and playfully intriguing (Tiger, 1992). To some extent, one could argue that it is precisely this individual attitude towards the pursuit of satisfaction and the power of pleasure that informs the level of pleasurability and playability people draw out of any given interaction. Through captivating experiences of involvement, challenge, immersion, investment, internal change and social interaction, people persistently explore the power of play and pleasure and the ambiguity of playability. In order to explore a ‘theory of playability’, a brief outline of the theory of play should be briefly presented. Johan Huizinga’s (1938; 1998) seminal book “Homo Ludens” advanced play not as an inconsequential and biological phenomenon confined to the sphere of childhood, but rather as a cultural one – i.e. a special form of activity separated from everyday life with a social function which involves experiences of great fun, pleasure and enjoyment. Another classic in play theory is Roger Caillois’ (1961) work “Man, Play and Games”, which extended and in part disputed Huizinga’s claims, by suggesting that the power of play is important to culture insofar as playthings as games, toys and other entertainment gadgets are historical residues of culture and the foremost triggers for playful activities. Caillois’ typology of play (competition –agon, chance –alea, simulation –mimicry, and vertigo –ilinx) also yielded another valuable concept: the notion of a continuum between free play or improvisation (paidia) and goal-oriented and rule-bound play (ludus). This contribution about ‘freedom and rules’ is regarded as the first conceptualization of play and game as complex systemic interactions, instead of straightforward leisure activities or cultural practices. In terms of game theory (following from the mathematical theory of games the study of strategies in a variety of situations), Brian Sutton-Smith’s (1997) book “The Ambiguity of Play” contributed further to this view of structured games by developing notions of control and system and thus proposing play as an exercise of voluntary controlled systems. The application of pure play theory to game studies and its relationship with rules and computer game design is also extensively discussed by Katie Salen and Eric Zimmerman (2003) book “Rules of Play: Game Design Fundamentals”, which reveals a contemporary tendency to associate the concept of play with the word game-play, in particular in media studies, game theory and Human Computer Interaction research. Ultimately, the concept of play can also be positioned within the post-modern literary and philosophical domains of Deconstructivism, which uses play as a programmatic term for the process of signification (semiotics) and the reconstruction of language and narrative between the realms of the imaginary/fictive and real life. Similar to game storylines, the literary text is the result of a process of fiction-making, to which play is the mode of mediation between reality and imaginary worlds. Conclusions: playing with paving design Following the previous outline of play and game (i.e. activities of fun and playful satisfaction), it is possible to draw a parallel between the previous conceptions of ambiguities, distorting realities, paradoxical illusions, fictional worlds and embodied movements with the concept of playability pleasures. Since the ‘playfulness’ and pleasure taken out of any given interaction is directly related to the user participation, involvement, immersion, investment and satisfaction, it should be this playful diversity of users’ experiences, capabilities and expectations that should inform the design of our surroundings. This means, for instance, that the design of pavement landscapes should involve the user as co-producer in ‘designing’ or defining a playful space.By suggesting pavements of pleasure, anamorphic landscapes of illusions and way-finding walking notations, the experience of space and time (e.g. when waiting or traveling) may be challenged, accentuated or enhanced. In spaces of travel and landscapes of waiting, pavements as such may provoke playful experiences and choreographies, suggesting new conceptualizations for aesthetic mobilities. Nevertheless, to further assess these prepositions, more experimental design work in this area is needed. 8
  9. 9. References: Bairrada, E.M. (1985) Empedrados Artísticos de Lisboa. Lisbon: CML Impressa Municipal. Baltrusaitis, J. (1977) Anamorphic Art. Cambridge: ProQuest Information and Learning Ltd. Cabrera, A., Nunes, M. and Ruas, H. (1990) Olhar o Chão: a Glance at Portuguese Mosaic Pavement. Lisbon: Impressa Nacional-Casa da Moeda. Careri, F. (2002) Walkscapes: Walking as an Aesthetic Practice. Barcelona: Gustavo Gili. Coren, S. and Girgus, J.S. (1978) Seeing is Deceiving: the Psychology of Visual Illusions. Hillsdale, New Jersey: LEA Publishers/ John Willey & Sons. Gregory, R. (1997) “Knowledge in perception and illusion”. Phil.Trans.R.Soc.LondonB, 352, pp. 1121-1128. Ingold, T. (2004) “Culture on the ground: the world perceived through the feet”. Journal of Material Culture, 9(3), pp. 315-340. Leeman, F., Elffers, J. and Schuyt, M. (1976) Hidden Images: Games of perception, anamorphic art, illusion from Renaissance to the present. New York: Harry N. Abrams. Lisney, A. and Fieldhouse, K. (1990) Landscape Design Guide – Volume 2 Hard Landscape. Hants, England/ Vermont, USA: Gower Publishing Company. Matos, E. (2004) Lisboa das Calçadas, Pavements of Lisbon. Lisbon: CML Impressa Municipal. Naukkarinen, O. (2005) “Aesthetics and Mobility – a short introduction into a moving field”. ContemporaryAesthetics [online], Special Volume 1, December 2005. Available from: <> [Accessed 14 March 2006] Ruby, I. and Ruby, A. (2006) Groundscapes: the rediscovery of the ground in contemporary architecture. Barcelona: Gustavo Gili Stonor, T., Arruda Campos, M.B. and Smith, A. (2002) “Towards a walkability index”. Walk 21C – 3rd International Conference Steps Towards Liveable Cities, San Sebastian, Spain. Tiger, L. (1992) The Pursuit of Pleasure. Boston/ London: Little, Brown and Company. Virilio, P. (1991) The Aesthetic of Disappearance (trans. by Philip Beitchman). New York: Semiotext(e). Wade, N. (1982) The Art and Science of Visual Illusions. London: Routledge & Kegan Paul. Wade, N. (1990) Visual Allusions: Pictures of Perception. London/ Hillsdale: LEA Publishers. Warner, M. (2004) “Camera Ludica”, in L. Mannoni, W. Nekes and M. Warner (eds.) Eyes, Lies and Illusions, pp. 13-23. London: Hayward Gallery/ Lund Humphries. 9