Never mind drawing a straight line. Kathleen Becker was having trouble with her curvy ones.

Becker, 60, an office manager from Northeast Philadelphia, bent over a coaster-sized square of paper, laboring to make a series of gentle arcs that would, when finished, resemble the underside of a woven basket.

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"I just did it wrong again!" she lamented, squinting at her inked lines. "I keep doing it backward."

"No, you're not," said Katy Abbott, the instructor of that evening's Zentangle class. "Your lines are just curving the other way."

In Zentangle, a meditative drawing practice that has scribbled across the globe since its creation nearly 10 years ago, there are no erasers, no apologies, and - as Abbott kept reminding the four women gathered around her dining room table - no mistakes.

Instead, Zentangle emphasizes mindfulness, a state of calm absorption reached by inking repetitive patterns onto small squares of paper. It appeals to people who don't consider themselves artists; Abbott's class included a calculus teacher and a woman who sells personal security devices.

Zentangle also captures a perfect 21st-century paradox: an antitechnology art form (no batteries, no software) that owes its rising popularity to blogs, YouTube videos, and savvy online marketing. Even Rosie O'Donnell creates Zentangle drawings, selling them for $50 and $100 in her online Etsy shop to raise money for a medical research foundation.

"For many people, the pressure of making an apple look like an apple stops them from making art," says Terri Greenberg, 53, a Zentangle teacher in Flourtown who has taught classes at Main Line School Night and Mount Airy Learning Tree. Zentangle, she says, doesn't intimidate people; it's abstract, small-scale, and accessible. "In Zentangle, even the most complicated pattern can be broken down to simple strokes."

Like any leisure-time pursuit (square dancing, mah jongg, yoga), Zentangle has rapidly become its own world, with disciples and skeptics, purists and innovators. Disciples say Zentangle brings them focus and confidence; skeptics counter that it's just doodling with a fancy name. Purists create tangles only on squares of imported Italian paper, using black Sakura Micron pens; innovators will grab a fat permanent marker and tangle anything that doesn't move: a pink umbrella, a pumpkin, a paper plate.

Zentangle even has its own creation story, told in a just-published book by its founders, Massachusetts couple Rick Roberts and Maria Thomas. The Book of Zentangle, published in September, combines Thomas' lush and detailed artworks with the couple's earnest philosophy of making art.

Nearly 10 years ago, Thomas was a well-known calligrapher and designer of high-end stationery; Roberts was a Renaissance guy who had been a cabdriver, a typesetter, a maker of American Indian flutes, and, for 17 years, a monk.

One day, Thomas was working on a large illuminated letter - it might have been a capital B - inking a simple, repetitive design into the letter's open spaces. When Roberts barged into her studio, he startled her out of an artistic reverie.

"It was like a daydream of comfort and peace," Thomas recalled. "I'm always doing 10 things at the same time, but this slowed me down. It was very Twilight Zone-y. We thought: We can teach people how to get this feeling."

The two went away for the weekend - one took notes while the other drove - and brainstormed the name, the theory, and the practice of Zentangle. They wanted to use high-quality materials; they wanted a DVD with nonverbal instructions so there would be no language barriers. They wanted to address all the reasons why people claim they cannot be creative.

"People would say, 'I don't have the time, the skill, the confidence, the money, the tools, the place,'" Roberts says. "That's why we came up with the 3½-inch square," a portable "canvas" that can be filled in 15 minutes. And while he and Thomas certainly encourage the use of their $49 Zentangle kit with its creamy papers and needle-nosed pens, people can, Roberts says, "do Zentangle with a stick in the sand at low tide.

"This is so untechnical, so personal, intimate, and physical," he says. "It's a wonderful counterbalance to so much electronics."

The couple taught their first class in 2004, to the members of a professional lettering society. They offered free sessions at their local library and at bookstores. Now they present $1,200 weekend seminars several times a year to train others to teach Zentangle; to date, more than 700 people have participated. There are CZTs (certified Zentangle teachers) in South Africa and Australia, Italy and Taiwan, along with 44 states and the District of Columbia.

The Philadelphia area is home to a handful of Zentangle teachers who have studied with Thomas and Roberts; they, in turn, have taught the art form to kindergartners and master's-degree nursing students, cancer survivors, and members of a nonprofit board on their annual retreat. Classes typically cost between $20 and $45.

The Chestnut Hill Starbucks featured an exhibition of Zentangle drawings in 2011; their creator, Terri O'Donnell, does Zentangle as a daily practice, the way some people meditate or write down their dreams.

O'Donnell, a life coach who lives in Wyndmoor, even taught Zentangle to guests at a 60th-birthday party last March. That's where Philadelphia attorney Mark Seltzer first came across the practice. A self-described "pen freak" and obsessive doodler - he says colleagues forbid him to keep original documents on his desk because he can't help decorating the margins - Seltzer created his first Zentangle and was hooked.

"I was immediately attracted to the Zen part of it, the focus," he said. "I'd do one at the start of my day and get completely absorbed. Then I started to see it as more of an art form."

Like many Zentangle enthusiasts, Seltzer has broken from the constraints of the small tiles to make larger pieces, using different kinds of pens. His pal Pesha Leichter, who hosted the Zentangle birthday party at her Mount Airy home, makes notecards of her finished drawings and is creating a tangle on a piece of hard-sided fuchsia luggage.

Both Seltzer and Leichter say Zentangle has changed the way they look at the world. "Once you start to do Zentangle, you notice things," says Leichter, pointing to the pattern on the embossed copper tiles that line Seltzer's kitchen. "Architectural details. You think, 'Maybe I can use that . . . .' "

Back in Abbott's dining room, the teacher is guiding her students through the steps to make "hollibaugh," a pattern of crisscrossing lines that resembles a crazed freeway system glimpsed from above.

The women hunch over their tiles. They're already hip to the Zentangle lingo, so that when Abbott suggests, "You could aura your betweed with perfs," they nod as if she has spoken plain English. (Translation: You could create a halo effect on a pattern called "betweed" by drawing a series of small circles.)

After two hours, they place their finished and half-finished tiles in the center of the table to admire them.

"I want to go home and look up more patterns," says Alyssa Forney, 22, from Churchville, who attended the class with her mother. Then she adds, "You know, I was in a horrible mood; I was crying in the car before I came here. I feel great now!"

Want to Zentangle?

Here are some resources and local classes to get you started.

Books

The Book of Zentangle,

by Rick Roberts and Maria Thomas (2012)

Websites

www.zentangle.com The official website created by Zentangle's founders, with lists of Zentangle teachers across the country, a blog, newsletter, and Zentangle materials for sale.

A well-organized list of Zentangle patterns, with step-by-step instructions.

Local Classes

Intro to Zentangle Basics, taught by Frances Brooks, Dec. 5, 7 to 9 p.m.; Jan. 9, 7 to 9 p.m. Ohmygashi Studios in West Chester, ohmygashi.com.

Zentangle classes taught by Terri Greenberg, Saturday 1 to 3:30 p.m. at Woodmere Art Museum; Nov. 27 at Grace Epiphany Church (Mount Airy Learning Tree),

6:45 to 9 p.m., teezeetee.blogspot.com.

Beyond the Basics Zentangle class, taught by Katy Abbott, Dec. 11,

7 to 9 p.m. Presbyterian Church of Chestnut Hill, abbottglassdesigns.

blogspot.com.