AKRON, Ohio (MCT) — Mary Oliver Bethel loves the steel frog sculpture outside the Highland Square Branch Library, but she’d always felt it was missing something.

So she and some fellow members of the needle arts group Akron, Ohio, Stitch ‘n’ Bitch gave the frog princess some finishing touches: socks, a colorful scarf and a black mustache a la artist Frida Kahlo.

The dress-up effort was part of a public art installation last year by the group, which also covered light posts, pillars, tree trunks and even the bike rack outside the library with knitted and crocheted pieces. The crafters were engaging in an art form called yarn bombing or yarn storming, which is sort of like graffiti, but with fiber – and probably with a better public image.

Yarn bombers cover anything and everything with knitted or crocheted work, from tree trunks and lampposts to buses and military tanks. Even the famed Charging Bull statue near Wall Street and the Andy Warhol Bridge in downtown Pittsburgh have been targeted.

While the practice is mostly a form of public art, it also seems to have spilled over into the home, where it’s become trendy to wrap objects with yarn. Alphabet letters and bottles are especially popular, but just about anything is fair game – clothes hangers and lamp bases, coasters and charger plates, even Easter eggs and antlers.

“Yarn bombing is like a joke, you know. It’s getting people to look at things in a different way,” Bethel said. “… It’s like a knock-knock joke in a public space.”

How yarn bombing started isn’t entirely clear, but its beginnings are often credited to Houston knitter Magda Sayeg, whose first act was creating a cozy for the door handle of her boutique. In 2005, Sayeg founded a group of artists called Knitta Please, which started wrapping telephone poles, parking meters and other public objects with knitted or crocheted material.

The practice has since gone global. Many yarn bombers treat the art form as a stealth activity, with some artists using only code names, said Leianne Prain, author of “Yarn Bombing: The Art of Crochet and Knit Graffiti.” The practice may be illegal if it’s done without permission, but because the art isn’t permanent, officials often look the other way if it’s not obstructive or otherwise problematic.

Yarn bombers may create their art to promote serious messages, “but time and time again everyone says (their motivation is) joy,” Prain said in a phone interview from her home in Vancouver, British Columbia. “I think that’s something we haven’t always associated with graffiti.”

That’s been the motivation for Akron Stitch ‘n’ Bitch, which had yarn-bombed some light posts outside the Chipotle restaurant in Highland Square before it took on the library project. The brightly colored yarn and the use of a practical item like a blanket in an impractical way just make people smile, Bethel said.

She said the library project took about a month’s worth of planning and seven or eight people to create the knitted and crocheted pieces and install them by stitching the pieces together with yarn. Library administrators were in on the plan, so there were no issues with legality.

Yarn bombing tends to cross social boundaries, involving people of all ages and walks of life, she said. And thanks to social media, it has become a form of friendly rivalry. People typically post photos of installations online, spurring a sort of one-upmanship, she said.

Prain said she thinks the appeal of yarn bombing goes beyond its quirky nature, though. The use of yarn just seems to touch people in a deeply personal way, she said.

“Everybody has a memory,” be it of a baby blanket or a sweater knitted by a loved one, she said. “There’s a sentimentality to wool.”

Whatever the reason, Bethel is just happy people have responded to her group’s yarn bombings so positively and treated the work with respect.

“It’s just colorful fun,” she said.