Perhaps you yearn to express stifled artistic impulses. Perhaps you hope to make your mark in the world.

A crop circle, perhaps?

Don't know what crop circles are? Then somehow you've managed to miss all signs of the big new movie "Signs," which opened recently.

Now, crop circles -- those intricately designed geometric patterns found in fields -- will no doubt become fodder for the popular imagination and begin cropping up from Bangor to Buena Vista.

Crop circles are largely a European, and specifically a British, phenomenon. But the real question is: Are they merely hoaxes, the mischievous handiwork of clever nocturnal artists? Or are they cosmic graffiti, the hieroglyphic calling cards of aliens and extraterrestrials?

Who knows?

Anyway, why wait for a creative visitor from outer space when you can be the first on your block to fashion a dandy crop circle all by yourself?

You don't need a degree in semiology. A British group called Circlemakers offers a handy guide on the Internet -- www.circlemakers.org/guide.html.

With a little practice, you, too, will be able to produce "genuine ... scientifically proven, un-hoaxable patterns."

The guide is written in Britspeak, which is to say it is wickedly arch and steeped in irony. Some of it is easy to understand, but the guide veers into incomprehensibility when it deals with "earth energies," "ley lines," and "orgone accumulation."

Luckily, one of the founding Circlemakers, speaking from London, agreed to summarize the instructions in terms your average American could understand.

John Lundberg, 33, is a film student specializing in documentaries, and he owns a digital-design company. For the last 10 years, he also has been a circlemaker.

"We never claim authorship of individual formations," he said cagily, "and we don't like to talk about numbers."

Suffice to say, he and his confederates have become adept at making what he calls "large-scale complex formations" -- "big fractals" (mathematically repeating forms) that cover acres and are designed with the aid of a computer.

Are any of his formations, perchance, in the movie?

"Talk to Disney's lawyer," Lundberg quipped. "Let's just say there are genuine formations that appear in the film, and over the past year we made some genuine formations."

Lundberg considers himself an artist, and crop circles magnificent works of public art. Some patterns are immensely intricate. Circlemakers take pride, he says, in crafting precise centers and tinkering with the lay of the crop, which affects the play of light.

The challenge is similar to that faced by Michelangelo -- except circlemakers typically work in the dark, completing their masterpieces in a single night. They can only hope the details will show in the parts, and that the parts will add up to a pleasing whole when viewed from above.

"The formations in America don't compare to the stuff we do over here," Lundberg said. "They're very simple, and most of the time not very well made. Then again, maybe they were made by aliens, and maybe they're not very good at it."