Standing in an East End gallery, my attention switches from a wooden scale model of an inhabitable space that is wall-mounted at eye- level, to a full-size wood-lined room that isn't the same as the other but clearly refers to it.

The two-room maquette is open on one side so I can see everything within. Low to the right is a cat-flap which leads to a boxed-in tunnel in a room with table and chairs. The cat tunnel zigzags across the floor, rises then falls from the table, and its walls expand as it passes into the second room, which contains a tree. The piece is called The curse of the jaguar.

There is a young black cat in the gallery. It stares at me. Then it turns aside, licking its fur.

Nearby, the two-metre cubic plywood room is also open on one side. It contains a high table-top stretching from wall to wall. One chair rests on floor on the viewer's side of the table-top, two are on the other side. Low down in the right-hand wall is a man-flap, which I crawl through to enter the all-wooden structure. I'm now under the table. I keep crawling, conscious of my leather-shoed feet, my black-jeaned knees and the bare palms of my hands coming in contact with the floorboards. The corridor immediately bears right and its ceiling rises, allowing me to crouch and, a pace later, to stand in an alcove doorway. I've travelled a loop of only a few yards; I'm now at the other side of the table-top, with two swivel seats to choose from. This piece is called When you drink yourself under the table it is good to come back in through the door.

The black cat has disappeared into the man-sized corridor. Is it part of the show? As far as I'm concerned it is. It doesn't emerge out the other end.

So, the scale-model again. I am the creature that makes my way in through the cat-flap, is guided along the floor, scrambles its way up a slope, then almost immediately down again. I'm the larger, wilder creature that lopes into the second room and jumps into the tree. I explore the roof of the building via one branch, but sooner or later I slinkily pad my way along the other branch into the attic above the first room, and lie on the branch with a view through a rectangular hole down on the sad man sitting alone at the table with a bottle of spirits.

I wait until he's had far too much to drink. I sharpen my claws; I smother a purr; I resist the urge to laugh at the fool or feel sorry for him or roar his introspective head off; I pounce. It's sudden, it's far too easy, it's all over. But how am I to get out of this place? The cat corridor is inaccessible, the underside of the branch impedes a return leap, and I can't open the door. There's nothing for it but to finish the bottle of spirits while I mull this over.

And I drink myself under the table.

When I wake I don't feel at all well. But I can crawl, one knee in front of the other. And now I can stand. And walk to the table, at which I sit.

And drink myself under the table.

When I wake, I don't feel at all well. But I can crawl, one knee in front of the other. And now I can stand. And walk to the table at which I sit.

And drink myself under the table. God, how did I get into this vicious circle?

When I wake, I'm facing the opposite way. Man-flap! I crawl towards it, one palm after the other. And when I stand up I find myself outside, a free man.

I wander over to a third wooden construction installed by Julian Maynard Smith: The giant's doll's house. (All the works could be called this.) It is a fraction of an infinitely extending spiral staircase with attached rooms. Each unit is exactly the same but bigger, the wide end of one unit smoothly joining onto the narrow end of the next. These are about the right size for a cat, judging by the delicate paw marks on them, but I mentally extend the sequence. From cats to big cats to men to free men.

At home, I let Genghis into the kitchen. As I pour milk from carton to saucer he rubs the side of his jaw against the table's legs in anticipation. And his face is in the milk before the saucer even touches the floor.

Julian Maynard Smith is showing alongside related work by Ken Wilder at 97-99 Gallery, E1 (0171 729 3778), to 20 December.

'Personal Delivery', Duncan McLaren's book on contemporary art, is out now from Quartet (pounds 12).