At the Coppermill
In September 2004, the German sculptor John Bock turned the main gallery at the ICA into something like a giant treehouse, a cluster of cabins, platforms and dens bashed together out of plywood and hung about with tinfoil, blankets and washing-lines. To get between them you’d climb ladders and squeeze through tunnels, balance on walkways and clamber over hay bales. Installations of this kind are popular at the moment. They get rid of the separation between the observer and the work; you’re shifted out of contemplation into activity, and don’t stand in front of what’s there so much as traverse it or occupy it. The works that make the deepest impression are the ones in which the exploration of the space has some thematic or narrative purpose.