Oak Bluffs streets were crowded on this early mid-August evening, both with cars and pedestrians, but I found a parking spot on Penacook — my go-to street for summer parking in Oak Bluffs — and walked toward Union Chapel.

My feet heard the drumming before my ears did.

Each performance of Built on Stilts, the dance festival that completed its 18th season last night, begins with a drum circle. Anyone can join the circle. Anyone can get up and dance.

As the minutes move toward 8:00, the dancing around the drummers takes shape. The evening’s performers are warming up. Moves ripple around the circle. The dancers are so attuned to the drums and each other they seem to be of one mind.

This year’s Built on Stilts comprised eight evenings of dance. Each evening comprised 10 or 12 or 14 dances — and no two evenings are identical. If you make it to all eight performances, you’ll see each dance twice. You’ll see some of the same dancers working with different partners. You’ll see at least 40 different dances in all.

Warming up around the drum circle

Built on Stilts is like an umbrella, gathering dancers under Union Chapel’s soaring roof. As director and co-founder Abby Bender wrote in this year’s program:

“And so each summer B.O.S. participants juggle their schedules to come together and make new dances with parks and backyards as their training grounds. Built on Stilts has found its home in this beautiful performance space and has made possible the discovery of friends and fellow artists who might otherwise remain strangers. Collectively, we have built an inimitable summer dance community in which we may ALL share our love of dance with you, regardless of our ages and sizes, no matter what our various training and experiences may be.”

 And what a community it is! Grade school students, high school students, and adults of all ages. Summer visitors and year-round residents. Professionals and amateurs. Working together, learning from each other, egging each other on — and performing for a standing-room-only audience as multifarious as the dancers.

Each night Abby Bender thanks the audience for being part of the performance. It’s not hyperbole: you can feel the performers gathering up energy from the audience, transforming it into dance and channeling it back to the audience.

On the last three nights of Built on Stilts 2014, though, the line between stage and audience was more permeable than usual. Roberta Kirn, dancer, percussionist, percussion teacher, introduced us to “circlesongs,” a form that she learned from its developer, musician Bobby McFerrin.

Circlesongs can be sung by a handful of people, or dozens, or hundreds, or thousands. The leader comes up with a tune and gives it to the circle. Then she comes up with another, complementary tune and gives it to part of the circle. And another, and another. Pretty soon multiple layers of harmony are rising from this circle of friends, casual acquaintances, and total strangers.

A few of us have been singing circlesongs with Roberta at her monthly community sings. Why not introduce them at Built on Stilts? Why not indeed. She’d do it with volunteers from the audience. She encouraged us “regulars” to come in case the audience proved hesitant. Hesitant we weren’t: volunteers of all ages, sizes, and vocal ranges made a circle where the drummers had been, and led by Roberta the singers created a song.

Built on Stilts has been evolving for 18 years. Why am I so struck by the wonder of it this year?

Because last week I was witness to an arts-related event that was different in every way: the seriously misnamed Islanders Write conference. For this island writer, Islanders Write was demoralizing. Island writers and island writing weren’t much in evidence. In marked contrast, island dance and island dancers were all over Built on Stilts. Year-round residents were well represented in the audience too. And all this was happening in the middle of August. When people from New York, Boston, D.C., and points west flock to the Vineyard to attend events featuring musicians, actors, comedians, and speakers from New York, Boston, D.C., and points west.

True, dance, like theater and music, is a collaborative art. Writing, like painting, is a solitary activity, but it’s a rare writer who thrives on isolation. Writers are each other’s coaches and supporters, listeners and readers. A conference about island writing could be as expansive and energetic and multigenerational as Built on Stilts. Abby Bender and co-founder Anna Luckey set out to create “an accessible forum for making and performing dance here on the island,” and that’s what it’s become, on a scale they probably couldn’t imagine back in 1997.

You know what? So far the much-ballyhooed “creative economy” has looked like an extension of Martha’s Vineyard: The Theme Park, where year-round working people are mostly support staff. If it starts fostering events like Built on Stilts, I might just get behind it.