If your target audience is aged under five, you can't expect to rely on language to make a play. Perhaps that's why some of the most memorable and inventive physical theatre is currently being created by companies making work for children. Of these, Theatre-rites are perhaps the best. Their site-specific commissions for LIFT (Houseworks in '97, Cellarworks in '99) and for the Greenwich and Docklands Festival (Millworks in '98) were ambitiously staged installations, combining performance with puppetry, object animation, sculpture, video and sound.

The Lost and Moated Land was created for the Young Vic Studio by Theatre-rites' co-artistic directors Penny Bernand and Sue Buckmaster with designer Sophia Clist. The audience enter into a world constructed entirely from cones. Gauzy diaphanous cones float gently like stalactites from the ceiling: soft, padded cones rise to meet them from the floor. Into this dreamscape, a cone-shaped baby is born. Three performers (Zannie Fraser, Alison McGowan and Angela Michaels) manipulate the cone-headed puppet as he first learns to walk, and then, spurred on by an avaricious seagull who steals his favourite star, to fly. In pursuit of the seagull, the puppet embarks on an epic voyage of exploration around this strange, conical environment; climbing gargantuan peaks, traversing precipitous ravines and crossing the sea. His journey is hampered by a dragon whose concertina body is constructed entirely, you've guessed it, from cones.

For an adult in the audience, the show is every bit as absorbing as it appears to be for the pre-school children it's aimed at. It's no surprise that a show for children should prove to be one of the most inventive, sophisticated and transcendent pieces of theatre I've seen in some time. After all, children have boundless imaginations, no preconceptions about theatre and, best of all, no notion of a fourth wall. It's a shame the same can't always be said for adults.