PORTLAND, Oregon (Reuters) - Quietly knitting a sweater while nestled on the sofa of a yarn shop, the bookish, middle-aged woman who refuses to give her name doesn't look much like a provocateur from the urban underground.
And yet she is about to become a light-hearted guerrilla artist, willfully scheming to break the law in the name of her craft. By this time next week, she intends to join the clandestine local ranks of knitted-graffiti artists known as yarn bombers.
"I'll talk, but you can't use my name," she told Reuters in a recent interview, insisting on anonymity. "The last thing a yarn bomber wants to do is get caught!"
"Yarn bombing" refers to surreptitiously attaching knitted articles -- sweaters, socks, mittens, sleeves, caps -- to public objects such as statues, bike racks, mailboxes or lampposts.
This latest artist-as-tagger trend may not have originated in Oregon's biggest city; no one asked knows precisely where it got started. But it has won a growing following in a town where "Keep Portland Weird" bumper stickers are popular.
What motivates a yarn bomber?
"It's supposed to be a sort of a surprise, like, 'Look what happened when you were asleep,'" said the anonymous knitter from the yarn shop, who plans to fit her sweater over a tree outside her condominium.
Others, like Joleen Klubek, sound more complicated.
Klubek's yarn-bombing adornments of presidential statues in Rapid City, South Dakota, and on state "Welcome To _!" signs along the Interstate highway system are considered elevated examples of the art form.
But most of her work was done in Portland. And much of her creativity, she says, was driven by compassion.
"I would walk around downtown Portland and see a statue that I thought was 'naked' and whip something up for it," says Klubek, who recently relocated to the east coast and claims to be retired from yarn bombing. "My big thing in Portland was bike racks. I always thought they looked naked."
One popular yarn-bombing target in Portland is a statue of former Mayor Vera Katz on the promenade beside the Willamette River. Recently, a pair of knitted socks appeared on the statue's feet. Bike racks and unattended bicycles in bike-obsessed Portland also are singled out frequently.
But locals say yarn bombs can turn up almost anywhere.
Don McIntosh, a journalist, left his apartment one day to find "a crocheted yarn cozy on a telephone pole." Later, he found "a knitted sort of yarn ball thingy" adorning an outdoor plant. Clearly, a yarn bomber lives nearby.
Anonymity remains a hallmark of the yarn-bomber. One known locally as Slip Yum Yum, who recently moved from Richmond, Virginia, to Portland, would only contact Reuters via email through an anonymous third-party associate.
"We work hard to keep a low profile and only communicate digitally," said the go-between, who in turn would only self-identify as "Knit 1."
One reason for all the secrecy is to avoid any potential brush with the law. But so far the authorities in Portland hardly seem to be in the verge of a crackdown.
Kelli Sheffer, a Portland Police Bureau spokeswoman, said yarn bombing could be considered littering, but added: "If folks think putting a scarf on a statue is risky behavior, then we're glad they get a sense of doing something daring without being more destructive."
Editing by Steve Gorman and Peter Bohan