WHAT MAKES GOOD ARCHITECTURE? Everything is designed Few things are designed well Brian Reed Brian Reed efficiently condenses the problems of good architecture here in this succinct quote. However, snappy and witty as this quote may be, it provides little or no insight into the complexities and intricacies of design, or what characterises it. Architecture has been present throughout human history, from the ancient 7 wonders of the world, only one of which stands to this day, the Great Pyramid at Giza, to the new age of explorative architecture. So, when did we cross the line from architecture being a necessity, to architecture being an art? And what, in essence, is good architecture? NECESSITY It s cold, dark and raining. A primitive Homo sapiens stands on the top of a hill. He thinks only of one thing shelter. Since the dawn of time, our ancestors have been seeking out shelter from the elements to survive. Then, after we discovered that we could build our own caves to shelter in, the sky was the limit. The Indus river civilizations we re among the first to found cities and begin largescale architecture for the purposes of housing, business, government and industry. In fact, often all we can tell of ancient civilisations are the buildings they leave behind. However, they were not all necessity. These ancient civilisations had an appreciation for the aesthetics of buildings. By decorating the floors of important buildings with mosaics or experimenting with form of the structures themselves, these early peoples were already demonstrating an appreciation of the aesthetic qualities of architecture after only a few 1000 years of buildings. This is an impressive feat in itself. As such I would argue that necessity of architecture for the sake of shelter was the mother of architecture for the sake of art. This however, roots architecture in practical foundations, and as such architecture is definitively different art form from pure art, as architecture must always be practical in nature as well as aesthetic. This defines it from other art forms so far as they are not constricted by the bounds of practicality or possibility, and they are free from the utilitarian nature of humanity. However, this does not mean it should be dismissed as an artform, as people who do not appreciate pure art can often see the appeal of architecture and as such the appeal of a certain type of practical art. It also often has a longevity that many art pieces do not, as can be seen from the 5000-year-old Great Pyramid at Giza. Also, it extends upon the idea that practicality is an artform in itself, and the beauty of the organised chaos of human cities. Architecture in the collective sense is beautiful in itself, and this I feel is part of the random artform of architecture.
Architecture has evolved since then at an incredible pace. Roman and Greek architecture was some of the most imposing ever created and exemplified the power of these enormous empires. The age of empire and religion bred a new type of incredible architecture of a majesty that had never been seen before. This expansion in the meaning behind architecture gives it the importance we see today. It is partly due to this expansion that we treat the architectural profession with the reverence and respect that we do today. The efforts that states have gone to too protect architecture historical architecture are massive, as exemplified by UNESCO world heritage sites and other efforts, for example Listed Buildings in the UK. Having taken into account the historical and artistic qualities of architecture, we are ready to tackle the heart of the question itself. UNION FRANK LLOYD WRIGHT (1867-1959) FIGURE 1 Critical to the success of architecture is its relationship to its environment. Whether this be in contrast or in harmony, architecture must relate to and take account of. I think it is fair to say all good architecture has some association with its environment. The synchronised union between environment and architecture is one that is specific to architecture as an art form and is rare in the other pure arts. Frank Lloyd Wright was a pioneer of his art, I think it is fair to say. One might say that his most famous work is also his masterpiece, the wonderfully hidden building in southwestern Pennsylvania, Fallingwater. It has become a by-thought for architecture and an icon of modern architecture. However, it really exemplifies the nature of contrast with nature itself and the importance of good interaction in this way. It stands out both in its contrast to the natural surroundings, with the aggressive hard straight lines and rectangular shapes, which are not often found naturally in nature and in its harmony. CONTRAST Contrast is a dangerous creature to work with. As with all architectural techniques it must be thought through and done purposefully to aid a desired effect, mere accidental contrast is just bad design, and will often be seen as such. An unwieldy and not well-thought through contrast can be an eyesore and can degrade the perceived quality and aesthetic of the buildings around it. However, this is not
to say always so. Successful contrasts are often incredibly effective in making the building stand out or making us think. Daniel Libeskind s Jewish Museum in Berlin is a masterpiece in the use of contrast to invoke thought. He aggressively grasps at the problem of making a museum that is so full of terrible feelings and uses contrast to say We are not here to avoid but confront and move on. FIGURE 2 The angular and sharp edges of the building are uncomfortable, jarring and slightly frightening, and by using these features in direct contrast with the older building next door, Libeskind shows us the movement of history and the less happy events of recent times, and the future. Its interiors do not let up the visual and angular assault, and effectively subdue the visitor. This is a perfect example of the use of contrast for the provoking of thought, and the active use of hard, ugly shapes to convey the deeper meanings behind the building, and the story it describes which, like the building, is brutal, thoughtless FIGURE 3 and cold. However, contrast does not have to be used in this way, and more peaceful uses are definitely possible, and have been used to great effect. The London Shard, by Renzo Piano, is an example of this softer contrast. It stands far above the very lowlying city of London, it lies in an area dominated by brick and older buildings, but yet it still seems to be in its proper place. This is a perfect example of contrasting harmony with its environment, where the building seems contrasting but nevertheless natural in its place. FIGURE 4 We have bumped up against a problem that will confront us throughout this essay. The lack of consistency, and the impossibility of making sweeping generalizations about the subjective quality of architecture. But we need not deal with this problem now. A better use of our time would be to continue to explore the issue and decide later on the final answer to the question, if there is one to be had.
HARMONY Harmony too, is hard to get right. It does not necessarily suggest a disguise of the building, such as covering it entirely in grass, but a sort of mutual agreement between the building and its surroundings. This if done well, is also very effective. We can start with the new extension to the Tate Modern in London. By, Herzog and De Meuron is a great example of my point. It is an example of harmony with the existing converted power station. By using the same brick to build the extension, the building feels whole and complete, while still having something new to offer. It in itself might seem angular and aggressive to the idea, but it has a harmony in context to its environment which makes it such a successful addition to the entire complex. It continues FIGURE 6 on the idea of brick, angles, straight lines and glass strip windows, but does so in a way that it still feels different and new at the same time as integrating seamlessly. This is an effective use of harmony between a building and its urban surroundings, and the appreciation for context while at the same time being new and different. Of course, there are many more examples of the other type of harmony with nature. This seems the most natural course in many people s minds, hence the enormous efforts that have gone into this department. Singapore s simply stunning Gardens by the Bay development is an exemplar of this more common sort of harmony. FIGURE 5 Its incredible sprawling seamless fusion of green and glass, leaf and metal, are a beautiful example of the sort of bio-mechanical constructions that are possible to us today. Carefully thought through by the landscaping design team, Grant Associates, it quickly became one of the most popular, and definitely one of the most recognizable parks in the world. Using seamless integration of the randomness of natural form and the angular nature of modern materials, the park uses these factors
carefully to enhance the effect of the nature and its incredible beauty. The most prominently natural part of the whole development, and certainly one of its most impressive parts, is the Supertree Grove. FIGURE 7 The randomly generated natural structures of the steel with the integrated vegetation offer us a possible vision of the cities of the future and what they make look like, as we might move towards a more bio-mechanical fusion of civilization and nature as we proceed to colonize the entire earth. This sort of architecture is very effective when done successfully and, moreover, can also spark thought as to the future direction of our cities and society in general. UNION II FIGURE 8 So, does Frank Lloyd s Fallingwater exemplify these two disciplines of contrast and harmony? I think it is precisely because of its fusion of the two factors that leads so many to be draw to its pure form which nevertheless seems to be at one with its environment in an effortless way, Due to its clever use of the nearby river, cover from vegetation and natural brick to contrast the concrete. It is amazing to think that such an angular and modern building seems to sit so naturally in the setting which it does, almost as if it was not there at all. I think it is union that lies our first clue to good architecture. The union of a building with its environment. The union of a building with itself. And the union of contrast with harmony, a duet that when properly conceived and carried out leads to world-pioneering architecture of the quality of Fallingwater. Unity is key.
FORM ZAHA HADID (1950-2016) FIGURE 9 It feels uncomfortable, doesn t it. When a form, a shape, a construct - is not quite right. By just merely changing the sizes of the two middle letters in the subtitle Form, I may very well have made many squirm in their chair. But it is precisely because of our natural appreciation for, and connection with, form and shape that make it so valuable and important for architects to consider. A wrong triangle, an imperfect rectangle and the effect is ruining. The exploration of form is an art in itself and has been pursued as such by artists throughout the ages, and their obsession with the human form in particular. Architects however have a similarly difficult task, although very different, with interacting with form on a huge scale, while contending with the gentle sensibilities of the human mind. Too often are architects confronted with the classic phrase It just doesn t feel right Zaha Hadid is an architect that remains undaunted by the challenges this angle of architecture poses. Her designs are beautiful, different and have a flow to them that is many find hard to match. The way she grasps at impossible curves which would make a structural engineer shiver. This does, however, mean she is a world-famous architect whose buildings are found all over the world. She has appropriately been named The Queen of the Curve by the Guardian, a name she does not struggle to live up to. The Heydar Aliyev Center, shown above, is probably the most recognizable of her buildings. The flowing curves of the building remain unmatched, and its internal spaces are just as stunning. Inspired partly by the older Islamic architecture of Azerbaijan, the building, according to Hadid, takes inspiration from this architecture, such as parts of the infinite series that are prominent in Islamic architecture, and used it to inspire the infinity-symbol-like curves of the building as it draws gentle 3-dimensional curves over the flat square which it dominates.
CURVE The whole concept of form is defined by the shapes which it includes. Architecture is bound to its external form, and this form must be carefully considered to ensure that it conveys the right message and has the right feeling to it. Frank Gehry s Walt Disney Concert Hall in Los Angeles is an example of aggressive curves that are possible with modern structural construction and materials. The building seems a jumble of concave and convex curved surfaces, the building however is imaginative, and conveys its artistic interior. The flowing curves of its exterior are akin to the music onside the building, which now hosts the Los Angeles philharmonic orchestra. This exploration of form makes the building FIGURE 10 both experimental and eye-catching, and iconic in itself. Buildings are so invested with their exteriors that they often succeed or fail just on that feature. The form of a building is the way it interacts with the outside world, and as such the user. The form does not necessarily have to be curved of course. Any consistent collection of shape, or even inconsistent if intended as such, is a valid construct of form. There are also the cases of random and planned, natural and manmade form to consider. Random form may often seem more natural, and planned form more manmade, but this is not always the case. If we look quickly at the Guangdong museum in Guangzhou, China, is a quick example of how random design is not necessarily natural in form and can feel extremely mechanical despite its random nature. Modern metropoli often evolve in this man-made yet random way, and the slums of Bangladesh or Sao Paulo are saddening but good examples of this sort of natural hive-like expansion of humanity. Purposeful computer-generated randomness is more common for natural tessellating structures that have the feel like they were created by swarm-animals such as ants, or how trees grow, in fractal patterns. Nature that has a lot of greenery is often deigned in this way, using computers to generate FIGURE 11 FIGURE 12 random and natural-seeming lines between pre-defined nodes. This method was used heavily in the Supertree Grove in Singapore to create the tree-top like tops to the steel trees while giving them a very high structural integrity. This is an example of manmade-random design, in its use of computergenerated randomness. We need not run through every single possible combination, there is sure to be a building somewhere in the world in that style. What s more important is that the combination is well thought through and appropriate to the building, and its external aesthetic form is properly considered, or the building is clearly no longer good architecture. Buildings depend so much on their external looks that this is critical to good architecture.
SPACE Space, like the exterior, is also vital to the success of a building. The most successful buildings must have a stunning interior as well as exterior to retain the hearts and minds of the public. Some buildings even eschew exterior architecture in favour of stunning interiors. The British Museum in London has a basic older-style exterior framework of columns and stone that reflect its older heritage, as the buildings are original, but the Great Court designed by Foster and Partners, changes the entire building, just through its amazing use of space to transform the old square that used to stand in the middle. Th vast glass-enclosed space of the great court partly conveys the magnitude of history itself, which the British museum is devoted to. The library in the middle, partly as an addition FIGURE 13 and partly to hold up the enormous unbraced glass undulating roof to the great court, seems impossibly huge and sheer vertical in the building. It dwarfs the visitors in reflection of the knowledge it contains dwarfing the individual in importance. Yet this space succeeds again and again into pulling visitors back to the building and is often the only thing visitors can recall after having left, the sheer sense of space. This shows how important space and interior is to users and to the entire vision of a building, and the effect it exerts on the world. This building, or at least addition, is a good example of a structure entirely composing of its interior, as the exterior is impossible to actually see, save from the air. FIGURE 15 FIGURE 14 The Sydney Opera House is good example of where a iconic outside form hosts an equally stunning interior to match. Jørn Utzon created this world-famous piece of architechture by playing with the folding of paper. However he did not only focus on the exterior design, but also considered the vast spaces of the interior concert halls and how they should connect with and enhance the external qulality of the building. This fusion of exterior and interior is present in this piece, but not in the ideal way. I m not claiming the Sydney Opera House is a bad piece of architecture, not at all. But the mix is not quite ideal as the interior does not really seamlessly flow with the exterior of the building, and the two are not flawlessly brought together. Each is stunning in its own right, but there is not necessarily the unity of design that might have been possible to achieve. For this we must return to Hadid
FORM II We return to one of Hadid s masterpieces of architecture. The Heydar Aliyev Centre is a building that encompasses two complimentary qualities of interior and exterior in perfect harmony. By using topological tricks in her mobius-strip like structure the building seems to flow, as its external form continues seamlessly into its vast curving internal spaces without pause for breath. It is successful in form precisely because its exterior is its interior, as suggested by the mobius strip. When visitors think of the building they do not see it as a great outside and a great inside, but as one FIGURE 16 FIGURE 17 completely coherent idea, as if the inside was merely an accidental addition which happens to be enclosed. The building is so striking because it feels whole, at one with itself. Zaha Hadid s masterful grasp of form is the key to this success. The queen of the curve used two of the most famous curves possible, the infinity loop and the mobius strip, to exemplify the new, unified Azerbaijan, free from the old Soviet rule and pioneering a flowing, modern and infinite suture. It s a building, I feel is still unmatched in architecture. Not due to great size or complexity, but due to its simple yet striking design, one which feels impossibly natural, manmade, random and planned all at once. Form is critical. Without it, the building will never fill the visitor s imaginations, and without it a building can never become good architecture. Form is key.
IDEA IDEA Thomas Heatherwick (1970-) FIGURE 18 It s certainly different. No other building in the world is in any way like Thomas Heatherwick s UK Pavilion for the Shanghai World Expo in 2010. If anything, it doesn t really seem like architecture at all. But there is something about it that caught people s eye so much so that 8 million people went to see it, making it the UK s most popular tourist attraction and it wasn t even in the UK. This is amazing enough as a feat, but what makes it a good piece of architecture? It s something in the ideas behind it. It is the power of the idea that can carry a building far beyond its physical confines. The tower of Babylon is a famous ancient mythological example of this. Far more important than the brick on which it supposedly rested was the idea behind it as being a unifying force of humanity. In the same way the white house represents the USA and the Kremlin represents Russia, perhaps one of the most important, or the most important, part of a building is the its idea, its ideals and its grasp on the imagination. The bricks, as it were, come second. Heatherwick s studio was one of many entrants into the competition to design the UK pavilion. They had a specific challenge to win the prize for best pavilion. Also, the UK had a smaller budget than many other countries for their pavilion. Although many of the others were extremely extravagant and expensive, but few matched the Unity, Form and Idea behind the UK pavilion. Inspired by the UK s advancement in botanical science, and convinced that they had to avoid any sort of technological devices such as touchscreens and projections, as all the other pavilions would be depressingly full of these, Heatherwick decided to eschew complexity for simplicity, and go with a very simple design that included a large collection of seeds, cast into the heads of every hair on the outside of the building. It is a truly impressively coherent and impressive idea, and one could talk about all its angles for hours. However, let s analyse the architecture in more detail. FIGURE 19
DETAIL Detail is one of the driving forces behind conveying an idea. To emphasise this, we will change tack for a little bit. For example, in the subtitle just there I added the first bit of coloured text to be seen in this piece. And it grabbed your attention, I m sure of that. But it is detail that conveys ideas. All of the titles and subtitles have had typographical tricks attached to them to emulate their idea, as I m sure most readers will already have noticed. But I use this as a point in itself, to convey the deeper effects behind tiny details that change the entire picture. Small things, in our world of complexity, often have extraordinary effects. Let s start with my favourite example, depart from our world of architecture and take a detour into maths. FIGURE 20 Although it looks impossibly complicated and almost supernatural, this amazing pattern is created by a very simple rule:. Although it is so short, this equation (called a set) defines the incredible shapes of the Mandelbrot set, which became a pop sensation bred from maths, a rarity in itself. The maths doesn t matter it s the premise that something as infinitely complicated as the pattern above springs from such a simple root. The same with details. A simple little thing can suggest so much meaning and complexity in a design that when it is taken away, the design loses all its value. The same, of course, goes for architecture. Tiny details in buildings, such a crowd movement or even the handrails, can make a huge difference to the building. For example, the Guggenheim Museum in Bilbao, designed by Frank Gehry, is in fact covered in a skin of Titanium rather than the originally planned Aluminium. This minor detail is not noticed by most who visit this world-famous art gallery. However, Titanium has a slight gold tinge to its shine, as opposed to the coldness of Aluminium, and as such the building has a sort of golden glow about it, even in cold sunlight, a detail that gives the building its characteristic warmth. It should not be underestimated that such a small detail would make such a big difference to the project, yet it does. It s amazing that such small things can such big effect on the whole. A good piece of architecture could feasibly rest on the quality of the details alone. FIGURE 21
IMAGINATION Imagination why such an abstract concept? - one might ask. Despite its wishy-washy definition, I believe we underestimate the part it plays in architecture, and of course, in life as a whole. But leaving the philosophy to the philosophers, what part does imagination have to play in architecture? Imagination is critical from two main angles. The imagination of the architect and the imagination of the visitor. Starting with the architect, what do I really mean by this? Originality, many would agree, is hard to ensure. There will always be motifs from previous designs that will always creep into a new work. This is, of course, not to be frowned at. A healthy appreciation for inspiration is the framework of any good design. But to change a building from a patchwork of motifs into a whole unified idea requires a healthy touch of imagination, of the mental associations with the idea. There s a clear difference between a building that is merely a collection of parts and a building that has a clear vision. Going back to Heatherwick and Foster and Partners, let s take a look at one their joint designs. FIGURE 22 The Shanghai Bund Financial Centre, designed by both in tandem, seems to some to just be strange. But it has an originality to it that is completely unmatched. I must admit, it s very difficult to define what I mean by imagination. But however, you interpret my descriptions, it s clearly one of the most important parts of any building. Just as important is the space any building occupies in the mind of people. The feelings with which people interact with a building are extremely valuable to any architect. These are difficult to cultivate from the start, it must be said. People develop relationships with buildings over long periods of time, as they develop memories that they associate with the place. These are difficult for the architect to create artificially. But the architect can create spaces, environments and a building that is conducive to these sorts of personal connections with the place. It s possible to say that some buildings catch the public s imagination better than others. Why this is the case is difficult to exactly describe. Some of the building that catch people s imaginations are of mediocre quality compared to the all the other factors described throughout the rest of this essay. These buildings are still successful, often more so than an objectively better designed building simply because of their grasp on the public s imagination.
IDEA IIIIIII FIGURE 23 Heatherwick is full of ideas. The entire success of the pavilion rests not on its pure design, or form or aesthetics, however stunning these may also be. But the idea behind the unwrapped landscape being the wrapping paper, as if the central piece is a present to China, and the Seeds enclosed in the heads of the hairs, and the landscape being a place to relax, is what made this particular pavilion win the first prize for best pavilion design. The building has everything. There is detail in the walls, in the specially made surface for the landscape, in the idea to distribute the seeds among Chinese schools. And, amazing as this may be with its short-lived lifespan, people developed a connection with the UK, an emotional one, many thousands of miles away from the country itself. I could go on. The faint black lines in the central part look like the lines of the Union Jack. The walls have areas of shade for hot days, have maps of the green spaces in London I think my point is made. The sheer originality and imagination that went into this project made it the memorable piece of world architecture it became, despite no longer being an actual place. The idea, as it were, lives on. This building is now, amazingly, constructed in people s imaginations rather than in bricks and mortar, and is one of the few amazing buildings that do this. With detail and imagination, this building has become an extremely good and successful piece of architecture. Ideas are the final piece of the puzzle. Without an imaginative idea, the building will never succeed in the same way. So where do we go now?
ART Architecture is Art. It has all the defining characteristics of it, but more importantly fundamentally connects with the world in a way some art forms cannot. It has a complexity, depth and meaning that I can never hope to cover in just 5000 words. Possibly the most successful art form ever devised, it has a truly universal appeal. Such we have come full circle form Necessity to Art. We might now even say, on a bigger scale something more. Necessity breeds art. So, what makes good architecture? I think, to an extent, we have answered this too. Architecture is extremely complicated. It s unfair to summarise such an art form into a simple set of axioms. But, let me try. CONTRAST, HARMONY and UNION CURVE, SPACE and FORM DETAIL, IMAGINATION and IDEA Through these simple words springs a world of good architecture so diverse I could not possibly hope to tame it. But as we have discovered, small things lead to a complicated world, just as these words, no matter how small, lead to an art form that reaches every part of the globe. Architecture is moreover a statement, a mark of humanity, of the ages, of progression, of power. And, of course, it has a future. But for the buildings that do eventually get demolished, or left behind in the race for the stars, will live on in our imagination, in the way that we remember the hanging gardens despite their destruction. All of the pieces we ve seen have a combination of Union, Form and Idea. They don t all fit my specification, but that is not my point. Saying a building is good is like saying an artwork is good. I can tell you it is, but it s hard to say why. The words Union, Form and Idea I felt just about cover the unimaginable complexity of the subject. If you asked me, however, to pick one of the three, I know instantly which one is most important. It s Idea. Ideas live on, buildings fall down. Daniel Rebollini
BIBLIOGRAPHY Foster and Partners, 2018. Foster and Partners. [Online] Available at: https://www.fosterandpartners.com/ Frank Lloyd Wright Foundation, 2018. Frank Lloyd Wright Foundation. [Online] Available at: http://franklloydwright.org/ Grant Associates, 2018. Grant Associates. [Online] Available at: http://grant-associates.uk.com/ Heatherwick Studio, 2018. Heatherwick Studio. [Online] Available at: http://www.heatherwick.com/ Heatherwick, T., 20113. Making. 2nd ed. London: Thames & Hudson. Herzog and De Meuron, 2018. Herzog and De Meuron. [Online] Available at: https://www.herzogdemeuron.com/index.html RPBW Architects, 2018. RPBW Architects. [Online] Available at: http://www.rpbw.com/ Studio Libeskind, 2018. Studio Libeskind. [Online] Available at: https://libeskind.com/ Wikipedia, 2018. Frank Gehry. [Online] Available at: https://en.wikipedia.org/wiki/frank_gehry Wikipedia, 2018. Jørn Utzon. [Online] Available at: https://en.wikipedia.org/wiki/j%c3%b8rn_utzon Wikipedia, n.d. By Binette228 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31888310. s.l.:s.n. Wikipedia, n.d. By PA - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=45169992. s.l.:s.n. Zaha Hadid Architects, 2018. Zaha Hadid. [Online] Available at: http://www.zaha-hadid.com/
GRAPHICS: Fig. 1: Fallingwater Frank Lloyd Wright Fig. 2: Jewish Museum Berlin Daniel Libeskind Fig. 3: Jewish Museum Berlin Daniel Libeskind (Interior) Fig. 4: Shard London - Renzo Piano Fig. 5: TATE Extension Herzog and De Meuron Fig. 6: Gardens by the Bay Grant Associates Fig. 7: Supertree Grove Grant Associates Fig. 8: Fallingwater Frank Lloyd Wright Fig. 9: Heydar Aliyev Centre Zaha Hadid Fig. 10: Walt Disney Concert Hall Frank Gehry Fig. 11: Guangdong museum Guangzhou Fig. 12: Supertree Grove Grant Associates (Detail) Fig. 13: Great Court Foster and Partners Fig. 14: Sydney Opera House Concert Hall Jorn Ultzon Fig. 15: Sydney Opera House Jorn Ultzon Fig. 16: Heydar Aliyev Centre Zaha Hadid Fig 17: Heydar Aliyev Centre Zaha Hadid Fig. 18: UK Pavilion Thomas Heatherwick Fig. 19: UK Pavilion Thomas Heatherwick (Detail) Fig. 20: Mandelbrot Set Mandelbrot (Detail) Fig. 21: Guggenheim Museum Bilbao Frank Gehry Fig. 22: Shanghai Bund Financial Centre Heatherwick/Foster & Partners Fig. 23: UK Pavilion Thomas Heatherwick