Primer (15)<br></br>

Dude, I can see all the way to next week from here!

Carruth, a maths graduate from South Carolina, apparently decided one day he wanted to direct, so set out to learn the basic skills - editing, lighting, photography et al - then watched a bunch of films to see what the possibilities were. Then he made Primer "for the price of a used car" - $7,000, he claims, no doubt possible because Carruth produced, edited, sound-designed and scored the music himself, as well as playing one of the two leads.

Primer conveys a real sense of someone not so much making up the rules for himself, as struggling to master a craft, making the odd mistake and coming up with results that he couldn't have foreseen - which is exactly the film's subject. You could read the film as a metaphor for no-budget film-making: when his boffins black out their garage windows with bin liners, you realise how Carruth contrived to keep his own costs down.

After watching the film twice, I'm no closer to completing its radically jumbled jigsaw of a narrative, but here are the rudiments at least. Two young men, Aaron and Abe (Carruth and David Sullivan), are meeting in Aaron's garage after work to pursue some abstruse science project. We don't really know what they're trying to do, and no doubt Carruth doesn't want us to: everything they say comes at us in mumbled snatches of overlapping dialogue, a dizzying hotch-potch of ceramic clusters, liquid helium, parabolic curves, Tesla coils and Weebles. (Weebles? Go figure.) Parts of a fridge and a car get thrown in, and "seven point five zero litres of argon", but we're none the wiser.

Then a breakthrough happens: Abe tells Aaron that he's going to show him "the most important thing that any living organism has ever witnessed" (Carruth is good on the earnest hyperbole of geekdom). This turns out to be a fast-growing fungus, and signals the presence within the device of "a two-way time cul de sac" - which might mean little in hard theoretical terms, but is certainly an elegant metaphor. In short, Aaron and Abe have accidentally created a time machine, and although this may not seem startling as a science-fiction premise, what's novel is the way that Carruth's characters get there, through gradual, digressive fumblings: it has an authentic smack of feeling-in-the-dark experimental science.

It's at this point that Primer's narrative trickery becomes truly byzantine. At one point, the two men discuss building a bigger model of the machine, but worry about where to put it - the camera circles round to reveal that they're sitting outside a self-storage warehouse. We assume this is the corniest of "Eureka!" moments, but the joke's on us: for the machine is already built, is already installed in the warehouse, and just over there are Aaron and Abe, walking out of the warehouse - watched by Aaron and Abe. This lovely, cheap-as-chips perceptual trick makes us do a double take, and from here on, it's double takes cubed and squared all the way. The rest of Primer plays on the notion that our heroes are in the present, but also already in the future - an idea neatly summed up by the one flip but priceless gag that Carruth allows himself: "Man, are you hungry? I haven't eaten since later this afternoon."

It's at this point too that the Möbius-strip plotting becomes truly inscrutable. One American critic maintains that it all makes sense if you keep close tabs on the mobile phone calls throughout; I can't honestly say that tip helped me much. But Carruth doesn't want us to understand too much: a distorted voice-over narration at the end of a phone line confuses more than it clarifies ("From this, they deduced that the problem was recursive" - well, that's a great help). When Abe develops shaky hands and asks, "Why can't we write like normal people?", you wonder the same about Carruth - his narrative convolutions suggest some arcane form of screenwriter aphasia. But if this is how he naturally thinks, then fine - we get to see the world through the optic of a genuinely strange intellect, part movie autodidact, part Popular Mechanics tinkerer.

There's a rough stylistic brilliance to Primer: grainy, bleached-out Super 16 photography, epileptic flurries of jump-cuts, fades to black that literally leave us in the dark, and Carruth's skeletal score. Wrapped up in 77 minutes, with barely a second wasted, Primer is the latest addition to the canon of clever, one-off riddle-films that includes Pi, Memento, The Usual Suspects and the under-rated Suture. There's also a glimmer of Chris Marker's classic 1962 time-travel short La Jetée, although Primer can't compete for emotional or philosophical depth.

Indeed, Primer doesn't have much emotional charge at all, or even any palpable characters (let alone any female ones). It's purely logistical in its conception, and it comes as no surprise to read Carruth talking about film-making from the perspective of "problem-solving". Primer doesn't engage you in very profound terms: this is cinema as Sudoku puzzle. Even so, there's enough arrogant, mercurial brilliance here to make Primer quite mesmerising. I might even be tempted back for a third viewing, to fill in some of those gaps.