Step one: you see the gigantic picture, which takes up an entire wall of the darkened gallery. From 20 feet away, it fills your field of vision. Somehow the picture seems thoroughly familiar, yet it appears to show the aftermath of some catastrophic flood, where only a few skyscrapers and chimney-stacks remain above the water-line.
Step two: the brain kicks in and registers a surreal joke. It's really "just" a photograph of Dublin's city-centre, only they've chopped off the foreground and mirrored the skyline in the bottom of the picture. No wonder the city looks as though it's a little Venice, with the Central Bank and other landmarks poking out of the calm waters. "I knew I wanted to do it room-size before I knew what its content would be," artist Grace Weir explains, as a gaggle of young children ganders up to the image. "I was interested in scale as physicality."
Step three: the kids notice their own shadows. They have stepped into the beam of the projector on the floor which is showing the picture. Then they spy a narrow pedestal and the trackball on it (that input device which is like a sort of upside-down mouse), just waiting to be touched.
Step four: a boy, who's barely a head and shoulders taller than this pedestal, reaches up and gives the trackball a swipe. The giant image shoots off to the left, then to the right, following his hand, then it revolves a giddy 360 degrees. The entire landscape appears to be rotating around the room.
Yes, this is QuickTime VR, Apple's software for 360 panoramas, but it's more than just a bit of technology. It's a dreamy, almost cinematic moment: we seem to be standing in a sort of camera obscura for the digital age, a machine in which our own eyes play funny tricks.
"When you say `the image is flooded', that's a psychological condition - of your eye giving you a picture," Weir explains. "Linear perspective doesn't take that into account. Our eyes read the bottom as water and the top as air, even though they are exactly the same image - it's the psychology of the eye if you like. The QuickTime VR image is circular - there's no beginning or end, and it plays with our spatial sense."
Weir is one of the leading artists of her generation, and computer tools have featured increasingly in her solo exhibitions of the past 10 years - as have themes from the new science of chaos or complexity theory. But this latest collection of pieces, which also featured in last autumn's graduate show at TCD's new MSc multimedia programme, has none of the shallow, gee-whizz, cluttered gimmickry of many recent "digital art" shows.
It is profound, highly complex and mature, and is arguably Weir's most playful collection of pieces to date. And it's all about middles.
"There's a lot of talk about having multiple endings to narratives, but I'm not interested in closure, in the end of things or the beginnings, or of linear narratives," Weir says. "I'm much more interested in the middle of things, and in the time it takes for something to occur - its actualisation. When the viewer rolls the trackball, it's an unfolding of events in real time. Any work is about the unfolding of events in the real time of the human body. It's to do with lived experience and the body. And I'm not interested in the idea of so-called interactive media where there's no author and so on - I'm the author, I'm still telling a story. I'm wary of those debates. And the piece is not about QuickTime VR, the technological aspect of QuickTime VR - it's about the middle of a circular image where there's no beginning or end to it. Technology on its own doesn't interest me - it's what we do with it that interests me."
She agrees that experiencing QuickTime VR for the first time can be "technologically sublime", because of the way it plays around with perspective.
"QuickTime VR is exciting from a representation point of view, particularly if you look at the development of linear perspective in art as opposed to the wide-angle perspective of antiquity. Linear perspective is representation on a two-dimensional surface. And it has been incredibly successful, because we do tend to think of the world as made up of straight lines.
"But QuickTime VR is different. It maps objects within a cylinder. They reshape, they resize according to the mapping on the cylinder, not on a flat surface. So it's a small step away from this representation from a linear perspective on a flat surface. The panorama plays around with your spatial sense and there's that beginning of a feeling of 3D."
If anything, the piece deliberately restrains viewers. They can't tilt the image up or down (which QuickTime VR is well able to do). This was part of her decision to keep cutting things down and throwing things out.
"I deliberately wanted to make it simple and keep it simple - I'm not interested in the way a vast amount of multimedia has so many things happening as quickly as possible. I wanted to strip it down, and edit severely. The technology exceeds our philosophical ability to deal with it."
She quotes philosopher Paul Virilio on how the Internet collapses our sense of physical distance and attacks Renaissance notions of perspective. If messages (and people) can be sent anywhere on the planet at an almost instantaneous rate, our concepts of distance and space break down, as well as our notions of near and far. The perspective of absolute speed, of real time, supersedes the perspective of real space.
What did she think of the reactions to the QuickTime VR piece? "To be honest I was totally surprised, and pleased at it. I've never seen people react to my work in such a way. My 2 1/2year-old niece, well she was 2 1/2 at the time, reached immediately and started using the trackball - she was my ideal audience really."
The installation, called "and" (it's about middles and in-betweens rather than beginnings or endings, remember), has several other components. One piece has an almost Zen-like symmetry: it's a pair of videos of a stone dropping into a pond. The first video, projected onto the gallery's floor, gives an overhead shot of the stone falling. Directly above, projected onto the gallery's ceiling, there's another shot of the stone falling down, but this time it's taken underwater, with the stone coming towards the camera. An experience that's mind-boggling and head-turning. Literally.
"Again, it's air and water as interface. When you see the videos of the stones dropping, you think this is happening first, and that's happening second. The time it takes to turn your head - the turning point - is the point of the work. You can't see both videos simultaneously, so the turning from one to the other becomes the lived experience of the work.
"It's about exploding out the idea of the middle. The gallery space we inhabit as viewers becomes the middle, the space in-between, the interface. We hear so much nowadays about `the interface' in computers, but the interface is much, much bigger and causes many more effects than we realise."
Weir neither fetishizes computers nor runs away from them. Instead, she creates a haunting mixture of physical and virtual materials, tools and spaces. But she finds herself "switched off" by the tyranny of the PC interface, the shrunken "box" in the corner of the room. Hence the mesmerising scale of the IT]QuickTime VR scene, and a further component of the exhibition a few feet away. A stone, about a foot in diameter, sits upon a sort of diving board. And onto the 3D surface of the stone, a projector (linked to a PC behind the scenes) traces the strange graph of a Lorenz attractor - the ordered structure within an apparently disorderly, non-linear stream of data.
Elsewhere in the exhibition, a pair of monitors shows (a) a video of a butterfly fluttering against a glass window, and (b) a still image of a body scan, a cross-section of a human heart and lungs, with echoes of the butterfly's shape, and more resonances of chaos theory.
Add together all the components - from the butterfly video to the pebble falling into the pond and the laser tracing non-linear equations on the stone - and you'd almost feel you were in a science exhibition. Science is a major part of Weir's art, and several of her shows make direct references to James Gleick's ground-breaking book from 10 years ago, Chaos: Making a New Science, and to various equations and models it explains - such as meteorologist Ed Lorenz's equations and his now legendary "Butterfly Effect". Was Gleick's book a major influence?
"Yes, absolutely. I was a real maths and science head at school, and when I read Gleick it was the first time I'd related to science as a source of inspiration, as a place where things were happening as exciting as philosophy and art. I loved his accessibility too - and he presumes upon the intelligence of his audience. It's not a simple book - he writes about it in an extremely complex fashion but it's so accessible. Science is becoming not just far more popular, it's also far more questionable if you know what I mean, and accessible."
She was also excited by the way divisions were breaking down within science at the time, between geologists and weather forecasters and mathematicians. It's no coincidence, too, that her own work has jumped from sculptures to photography, video and computer-based pieces.
"I would like to be more disparate in my work, to draw together a found object, modelled objects, drawings - you can see that in places such as the Science Museum in London and nobody thinks twice. In fact science embraced the use of multimedia in those kinds of spaces far more effectively than art galleries."
She argues that it's no coincidence that non-linearity is emphasised not just by modern science but by literary theory, music and visual art. Perhaps linearity will turn out to be a short aberration in the history of ideas and culture, rather than the dominant paradigm.
Weir is not sure when she can do the exhibition again - the first showing in the Douglas Hyde Gallery lasted hardly a week. "I'd love to edit and extend it but it costs a fortune to put it on, and a lot of equipment - it takes four projectors, four video players, two computers. . ."
And one very, very large wall.
A workbook and version of the show is at www.cs.tcd.ie/courses/ mscmm/gradshow/and/