An Oak Tree, Traverse Theatre, Edinburgh <!-- none onestar twostar threestar fourstar fivestar -->

Tim Crouch's tricksy new play has become one of the most talked-about shows in town. In each performance of An Oak Tree, Crouch is joined on stage by a second actor who has no knowledge of the play or its subject matter. He or she is given whispered, spoken, written and private instructions by Crouch.

The audience finds itself watching a horribly hesitant hypnotist doing a gig while the opening chorus of Carmina Burana blasts out. A child has been killed on the way to a piano lesson in a road accident involving a hypnotist. The dead girl's dad (played by the second actor) has directed his feelings for his daughter towards an oak tree growing near the site of the accident. When he volunteers himself as anonymous subject for hypnosis the story branches out. Crouch developed the whole concept in collaboration with the poet and performance artist Andy Smith.

Given the stop-start stage directions, any one of us could play the subsidiary role, as long as we could bear to be patronised by the oleaginous Crouch, who keeps "encouraging" his opposite number - who was a game, if slightly bewildered, Ant Hampton, the night I saw the show.

To have Hampton reading out a sentence (written by Crouch) praising the script was trying the audience's tolerance. Some people apparently find an emotional core to the show. That is, to me, the most unexpected and inexplicable trick of all.

To 28 August (0131-228 1404)