I spot one from a distance – a cluster of people standing in worship around a glinting monolith. They stand in reverence, like some kind of pagan ritual, bunches of Narcissi gazing at their distorted, upside-down reflections, drawn into the sculpture's mysterious orbit like the apes of 2001: A Space Odyssey. This is C-Curve, and here I am, hanging upside down from the muddy grass sky, poised above a lake of suspended trees. It's a simple, playful effect, slightly underwhelming to me in this moment, but enchanting nonetheless. "Now what's really fun is to walk around the side," says a lady, so I do, simultaneously taking in the convex and concave surfaces, upside down and the right way up all at once. The sculpture's curved backside reflects the stretch of genteel, ordered park beyond and I marvel at my pregnant form becoming even more pregnant as it balloons out in the mirror... but the spell is broken when I notice a menacing-looking man dressed all in black, with 1980s mirrored aviator shades. He is the security guard and he's having a very serious conversation with someone about how more barriers are needed around the work. He gets very upset when a man puts his tiny camera tripod on the sacred concrete plinth – concrete being renowned for its fragile nature. A small child tries to get a little closer to the sculpture but she is rapidly shooed away and I decide to move on too.
Next up is Sky Mirror, Red, which is distinctly disappointing in its reflective and world-turning-upside-down capabilities. Its dull red surface faintly depicts the whispy clouds above, but so faintly as to barely be visible. What is much more apparent is its perfect roundness, sat at the edge of the park's Round Pond. A group of swans float gracefully past, the silvery autumn sunshine glinting off the surface of the water, and the only thing that ruins this picture perfect scene is the horde of hormonal American students making sketches of it. "I am, like, sooooo inspired right now," drones one. Anish Kapoor isn't himself responsible for any of these things, of course, but he did choose the setting, and it's an interesting moment, created by a red circle in a round pond. A Japanese bride and groom appear incongruously in front of the swans to have their picture taken by the water's edge. The bride looks swan-like in her dress, which has a long, swan-neck piece of material trailing around her own neck. They choose to omit Kapoor's sculpture from the photographic scene. "It looks a bit dark and baleful, really, doesn't it," says a lady to her companion. I think that's why I'm starting to like it – it's not shiny and impressive like you think it should be, it's opaque and difficult, more edgy than I expected Kapoor to be in this setting. It's rubbish as a sky mirror (at least in this light), but it's successful as a work of art – just as long as you don't expect it to be a sky mirror. As the sun drops, it punctures the scene in an ever darker way, a hole in the picture, a blank spot, an absence.
Now for the witch's hat, Non-Object (Spire), which is being polished to perfection as I approach it. As I turn around, in the distance I notice a large church spire sillhouetted against the sky beyond the round pond, a visual echo across thousands of metres. The polish smells strong, and the polisher is the only human reflected in the surface of the sculpture – everyone else is kept away by a strict, museum-style barrier. Images of the surrounding trees and sky are elegantly drawn up the sharply peaking spike of the cone-shaped piece, and it is straightforwardly beautiful... if I could ignore the giant pile of dirty rags and polish currently cluttering up the adjacent grass. It would be much more serenely beautiful without the barrier too. A lady in a red jacket purposefully strides up to the polisher... and breaks down in tears. "Angus, I just can't believe what's happening," she cries. "Did all the fingerprints come off?" The degree of stress regarding the pristine nature of these sculptures is huge. Such quiet, contemplative pieces cause such consternation and fear. Heaven forbid that the 'public' should engage with 'public art'.
The last on my tour is another Sky Mirror, this time much much bigger and much more reflective – a giant disk, perfectly round, reflecting the pale blue sky and white/grey clouds. I stand looking across the Serpentine waters to the grassy bank beyond, the perfect circle carving out a section of silver sky in the green... more noisy teenage students arrive, and a couple start smooching on the bench next to me, once again punctuating my brief moment of meditative calm. But that's public, park-based sculpture for you, and I can't complain (even though the smooching becomes unbearable).
So what is so appealing about reflection? Are we all magpies at heart, drawn to shiny surfaces? It is just visual trickery that we like, expecting one thing and seeing another? The vast Sky Mirror stops people in their tracks – it's the most successful of the pieces in some ways, perhaps because of its monumental scale. It is big enough to take in a sufficient amount of sky to be really impressive. I thought perhaps it appeared to be more reflective and more exciting because the sun had come out, but now it's gone behind the clouds and the piece is still beguiling. It's the one you can see from farthest away – something as big as the sky needs something pretty big to reflect it – and it's trying to capture a little piece of infinity, after all. Rosie Spencer
Anish Kapoor: Turning the World Upside Down Kensington Gardens, London 28 September 2010 – 13 March 2011