A mathematics consultant was brought in to check the film's vital statistics. "It's funny," says Natali, "because the maths consultant said, `if I were really to design this place, that would get me another PhD. To work out all the permutations for those rooms would be so complex'."There were other problems. The wood and plexiglass set was like a furnace, and the different colours had a strange effect on the actors. Occasionally, moments of visceral violence erupt.In some ways, all films are mathematical problems, requiring directors to think in three dimensions, to draw up their own visual geometry and orchestrate time and space.

Filmed entirely on a 14-ft square set in a Toronto warehouse, Cube's labyrinth presented Natali with a more elaborate puzzle than most. "The idea originally came from the need to shoot it all in one location," says the director, "but it was actually a very restrictive set to work on. Obsessed with finding perfect order in a chaotic world, Max works feverishly at his massive computer, taking time out only to visit his mentor for the odd game of Go. As they try to escape, Natali's cop, thief, maths student, psychologist, autistic adult and surly architect stumble across a deadly collection of booby traps, while picking their way through their own moral maze of conflicting personalities and beliefs.Why are these characters here? Natali chooses to keep the audience as much in the dark as the characters, so that they, too, can share in the confusion and claustrophobia. More literal in its nightmare, Cube sees a seemingly random sample of strangers trapped in a giant, Chinese box of interlocking, different coloured chambers that resembles some lethal Rubic's cube. An intriguing play of Pythagorean mysticism and uncanny imagery, Pi makes for fascinating and sometimes unsettling viewing.Mathematics meets horror sci-fi once again in Canadian director Vincento Natali's visually inventive Cube. But with this much originality, who cares if the film's logic doesn't bear scientific scrutiny? Strikingly shot in binary black and white, this richly atmospheric film is more than the sum of its sums.

Pi, with its wild sci- fi speculations and conspiracy theories, is undoubtedly the latter, using sometimes hokey plot devices to figure a metaphysical frisson from maths' sexy permutations. Caught between a group of Hassidic Jews plotting the divine importance of Talmudic numerology, and the more worldly interests of a shadowy Wall Street brokerage house, Max finds himself increasingly plagued by monstrous migraines and paranoia. As he seems to be reaching some kind of mathematical epiphany, however, his story takes a dark turn. That was my last contact with the Czechoslovak embassy for 21 years..