This latest inflatable structure - 128 feet long by 104 feet wide, rising to 26 feet at it highest, its glowing interior colours generated by nothing more complicated than daylight, is called “Arcazaar”, and the name is apt. For this, the most ambitious yet of the structures designed and made by the Nottingham-and-Geneva-based artist Alan Parkinson, is not a single inflatable building, but rather a linked series of fantastically-shaped domes and towers. It is a Kasbah that takes Moorish architecture as its starting point and then, as Gaudi did in Barcelona a century or more ago, turns it into something highly organic, and distinctly ambivalent.

There is no mystery to the technology of such luminaria - they share that with the ubiquitous bouncy castle, and a number of inflatable sports halls around the country. All you need to keep them going are electric fans, and not very big ones, either. But what Parkinson has done, ever since he first started experimenting with these forms in the 1980s and went on the road with them a decade ago, is treat the inflated object as an immersive art experience, in which light, sound and architectural form combine.

Such “buildings” - there are three different Parkinson luminaria touring the world at the moment, and last year they jointly averaged 1,000 visitors a day - are interesting for the very fact that they blur so many boundaries. They are not quite architecture, not quite art, not quite entertainment - although their ephemeral nature and strict touring schedules does rather hint at the heady tang of the fairground. Parkinson aims to build a complete new one each year, always different from earlier models, which are then gradually retired. As with fairs and circuses, the luminaria are dependent upon good weather: they do not tour in winter, although - now that

What they offer is the chance for people to lose themselves - sometimes literally, since some of the luminaria boast internal mazes - in an environment that is more than somewhat suggestive of the interior of the human body. You might be within the aorta of the heart, for instance. Or, of course, back in the womb, surrounded by all those comforting whooshing noises. Your route takes you 300 metres through all this, from space to space.