In 2003, I walked out of a San Diego theater struggling to explain the movie I had just seen. This was bad news in a way because I’m pretty sure that I’d been assigned to review it for the newspaper.

Maybe not. Reviewing movies was not my full-time gig with the paper. But I knew I had to write about it.

“It’s like … It’s like.” I stopped. Closed my eyes. Inhaled.

“It’s like somebody just handed you this beautiful, intricate stained glass window in a box. Only the window is smashed into a hundred pieces. So you pick out the pieces one by one and look closely at each one, taking note of the shape, the colors, the patterns.

“You lay each piece on the table beside similarly colored and shaped pieces until, oh so slowly, a narrative begins to emerge. Now the confusion fades and the excitement rises. You are beginning to understand causalities and relationships.”

You don’t want it to end. The movie, I mean.

My friend told me that I’d spent the second half of that movie perched on the edge of my seat, gripping the back of the one in front of me. Like a kid at a Saturday matinee thriller.

The movie was “21 Grams” and it was directed by Alejandro González Iñárritu from the script by Guillermo Arriaga (who wrote scripts for “Amores Perros” and “Babel” which Iñárritu also directed). Those stories, too, were told in a non-linear fashion. Arriaga was nominated for the best original screenplay for “Babel” by both the Oscars and BAFTA. He won the Cannes award for best screenplay for another film, “The Three Burials of Melquiades Estrada.”

Arriaga is also the author of a half-dozen novels, including “Night Buffalo,” “A Sweet Scent of Death,” “The Guillotine Squad,” and just last year, “Extrañas.”

Guillermo Arriaga was the keynote speaker last night at the annual San Miguel Writers’ Conference and, as a personal hero, he did not disappoint.

Arriaga outlined a treasure trove of inside stuff on his own writing technique and thoughts in general on writing that would give ulcers to college writing instructors and writing workshop leaders. (I might have heard a few gasps in the room as he spoke.) Arriaga ought to be a hero to every kid who hates drawing inside the lines, every kid who balks at lists of rules, every kid who feels like an “other” among the over-achievers.

Let’s get it straight right now: Arriaga doesn’t like research, he doesn’t adhere to any one style of writing, he doesn’t plan out his writing, and he sure as hell doesn’t know what the ending will be until he gets there.

“If I already know the ending,” he asks, “what’s the point in writing?”

He doesn’t mind offending the reader when it serves his story. He believes his role is to make people uncomfortable. Stories should push your brain around. “Art is here to be confrontational, to move people,” he insists. “To offend is my purpose.”

“And when people say my books are not for everyone, I reply, ‘ Why not? I wrote them for everyone.’ “

Mind you, Arriaga isn’t talking about confrontation for the sake of confrontation or to get some sly kick out of pissing off bluenoses. He’s talking about writing that opens minds, challenges assumptions, forces personal confrontations, engages thinking and burnishes the truth.

You know, all the stuff that is terrifying the book banners and politicians in, for example, Florida.

Face it, it takes guts to be a writer. Especially that kind of writer.

“Every artist is doomed to fail,” Arriaga asserts. “We are doomed to fail.” In Mexico, he notes, one in 100 manuscripts ever gets published. The chances of second, third, and fourth editions are minuscule.

It takes courage to do that kind of work. Arriaga likens writing to asking five people to come up on stage and strip naked before the audience. The exposure — both literal and figurative — is terrifying and humiliating. Apply that to being a writer who has just put out his or her manuscript — those years of hard work — to set it up for ridicule, criticism, scorn … In case you are curious, nobody takes him up on the buck-naked challenge.

So, how does a writer survive all this?

“You write for your species,” he says. And I take that to mean the base audience that understands and appreciates what you are trying to accomplish. “My species may be very small. I don’t really know.

“Maybe I’ll die and get widely published. Sad. You are widely published — but you are dead.”

Why on earth would a writer with this outlook ever put words to paper? The reasons are both pragmatic and practical: “If I don’t write out my ideas, they will rot inside me” … “Also, I write to provide for my family.”

“Am I a good writer or not? I have no idea.”

Seriously? Yes, Guillermo, you are a very good writer. An excellent one if I dare say so.

And how did he get that way?

It started with William Faulkner’s “Sound and Fury” which Arriaga resisted reading for the longest time. When he did, “it gave me dreams. It lit up my insides.”

No uncoincidentally, “Sound and Fury” is a non-linear novel, the style Arriaga uses in many of his scripts. Some critics say reading Faulkner is “like reading a drunk.”

“He was a drunk,” says Arriaga in his defense.

Life is perhaps the strongest influence on Arriaga. “I don’t do research. My entire life is research. Indeed, a horrific near-death car accident that resulted in facial reconstruction was the genesis of the plots in both “Amores Perros” and “21 Grams.”

His famous and often-quoted line, “I am a hunter,” emphasizes Arriaga’s preference for drawing from real life rather than sitting in a library with a stack of books taking down copious notes. When he needed to understand the role of doctors, he went to work in a medical facility. For a novel on jails in Mexico, he didn’t need to get arrested and do time — he just grew up knowing a lot of guys who did just that. And they told him their stories.

“Everything in life is valued,” he said. And someday becomes the stuff of a novel or screenplay.

Not that he spends much time writing down his experiences in anticipation of that day. “I don’t write anything down. If it is a good idea, it will come back to me,” he said.

Here’s the part that made writing workshop gurus choke on their own syntax:

“There are no rules. Each story has a different way to be told. The writer is obliged to find the most organic way.”

Not necessarily a big fan of linear storytelling, Arriaga attributes a bit of his own style to a case of attention deficit disorder.

i discover voice as I write,” he said. “The story dictates its own style, voice, and structure. I have no plans before I start. We are not all capable of research, planning. Instead, we discover.”

“Some writers work with a (highly detailed) map. Some with a compass.”

It was liberating to hear Arriaga observe that the thing that literary pundits and critics think of as “style” isn’t suitable to all writers. Striving to write in a particular way when it is out of your reach or doesn’t suit you is self-defeating for writers. “It is better to create a world your readers have not seen before. Find the capacity to see places we have never been.”

Some writers are well-suited to the deep and dense writing of Carlos Fuentes. Others to the economic style of Hemingway.

“Write what you can, not what you want,” he admonishes. “To make peace is the best thing to happen to a writer. There are many narrative traditions, find the one that you can use, not the one you want.”

And then learn to respect everyone else’s writing.

For Arriaga the “hunter,” writing is like going into the jungle in search of the tiger — with only a stick. You poke the tiger but it goes where it wants to … or it eats you. “Few authors ever get the tiger into the cage.”

Arriaga shows marvelous humility: “I’ve never gotten the tiger into the cage.

“I have heard the tiger. I have seen the tiger. I have smelled the tiger. I’ve gotten so close to the tiger.

“And that, that is good enough for me.”