50th Venice Biennale

What to say about the Venice Biennale opening week? It was hot and there was a lot to see, although I'm not quite sure what everyone was looking for in an event that can reduce everything to visual and social blancmange. I never encountered two of the pieces that most interested me in Venice. One I searched for but couldn't find, and the other I only heard about through hearsay.

The first is a photograph of a donkey standing in a boat amidst an expanse of calm water that fades seamlessly into a pale blue sky. The light is the bright white light of Italian midday summer sun. The donkey is patient, noble even. Everything is crisp and still. It is such an absurdly perfect image it must be real. The second work involves another photograph: a picture of a woman. She is wearing designer biker shades and a necklace, which reads 'Heroin Kills'; she's smiling, she looks healthy, relaxed.

In Venice, Paola Pivi's Untitled (Donkey) (all works 2003) was printed on to a banner and hung high on a wall around the corner from the official entrance to the Arsenale. I imagine encountering such a cool image in the Venetian heat is soothing, its fabulous contradictions never once disturbing the image's seductive surface. In a town free of billboards the picture is all the more perplexing, revelling in the device of a spectacle that refuses to advertise anything. For all its references to stupidity or icons - the donkey, effigies being put out to sea - this is a smart work. Its openness and stubborn refusal to mean anything, while teasing you with its potential, are what make it so attractive in an environment where everyone can appear so desperate for conclusions.

Joanne Tatham and Tom O'Sullivan's HK Necklace is a piece of 18-carat gold jewellery. It is also a mutation of HK, a previous work which filled the space at Tramway in Glasgow, made up of six-metre-high, black, 3D letters that also stood for 'heroin kills'. As with HK, HK Necklace is context-specific. Here in-your-face, smack-addled Glasgow is replaced by the insidiously glamorous whirl of Venice. The necklace is fashioned in a 'name tag' style but with a cool El Lissitzky twist; both the gold and the conceptual swagger are expensive. Tatham and O'Sullivan invited a range of dealers, collectors, artists, associates and friends to wear the piece during the opening week, forcing the artwork into areas the creators themselves couldn't access. These were the places where the hardcore glamour (or the imagined hardcore glamour) of Venice might be found, the social spaces built on hierarchies and codes of behaviour that can be as addictive and damaging - as corrupt and wonderful - as any drug.

I never got to see two of the pieces that interested me most. One I looked for but couldn't find, and the other day I only heard about through hearsay.

So, are rumour, anecdote and the list of wearers all components of the artwork, as much as any of its physical characteristics? Why would you adorn yourself with such a necklace? And how can such artworld rhetoric be so lightly overlaid on such a profoundly banal statement as 'heroin kills'? The social hierarchies of Venice are not nearly as interesting here as the fact that people became complicit with these systems of exchange.

For all its ingratiating content HK Necklace is an elegant artwork; almost invisible as an object, it becomes overloaded with meaning as it spins on the tension between repulsion and desire. The attractiveness of such a beautifully prosaic frisson of danger is what makes it both peculiar and unpleasant. Conversely, Untitled (Donkey) keeps the viewer at a distance; despite its tough beauty it refuses to charm, luxuriating in the fact of its own image.

Both of these pieces are about looking and seeing, chasing desire and not seeing what you desire to see; about things being simultaneously meaningful and stupid; and about testing the limits of representation while remaining complicit with the status quo. One celebrates its own visuality while the other locates it elsewhere beyond the image, lost in rumour - yet both have a madness that you can't close down. Within the predictably reductive, grand narrative of Venice it is in the marginal spaces that the art still seeps through.