As a words person I've never quite found the vocabulary to do justice to physical theatre. Sometimes it's best just to stop trying to analyse what you see in words and let the eyes and emotions take over. That's what went through my mind on Saturday when I caught the last performance at the Lyric Hammersmith of Franz Kafka's Metamorphosis, adapted and directed by David Farr and Gisli Örn Gardarsson. It was brilliant but two days later I'm still hesitating about the hows and the whys. Gregor, the young travelling salesman who turns into an insect, is played by Gardarsson with astonishing physical and acrobatic skill. The upper half of the split-level set where Gregor exists is an optical illusion that tests our normal visual responses: the set has been turned through 90 degrees so the audience viewpoint is from above as Gardarsson clambers insect-like around the walls, provoking the disgust of his family. It's an astonishing performance, achieved entirely through movement. I think the key to its powerful effect is the contrast between the fluidity and athleticism of Gregor and the jerky movements of the rest of the family. Which one of them is 'normal'? At the end Gregor breaks through the ceiling and ends the play swinging lifeless from a long strip of red cloth as his family celebrate his death framed by brightly lit flowers. It's a heart-breaking scene which unlocks the many meanings of Kafka's story about humanity and inhumanity. The words spoken by the British and Icelandic actors don't matter very much because the meaning is in the movement, the design and the music. Unforgettable -- a show that rightly earned five Billingtons from the Guardian and wowed most of the other reviewers as well. David Farr isn't a household name but his track record is starting to be amazing.