“Whatever that is in the middle — that’s dope,” says one of three excited teenagers while pointing to the walls of Modica Way — the alley in the heart of Cambridge’s Central Square. He’s talking about Judith Supine’s street art, a 17-foot-tall highlighter-colored, wheat-paste collage.

What’s even more dope is how the grafitti-like art is public, lacks a corporate sponsor and is wholly legal. Supine’s piece is part of a huge project on the wall outside Central Kitchen (567 Mass. Ave., Cambridge) and in fact, the entire 81-foot wall is covered from top to bottom in a poster-painted 3-D graffiti-stenciled pastiche. The last week in October, Supine and 19 other artists met in Cambridge to create a public display of cutting-edge street art that defies description. More than a simple wall, the entire southeast-facing facade, from HVAC ducts to window sills (up to and including parts of the roof) are plastered and splattered with characters, words and colors. The art will remain there for all to see until the weather, or something else, washes it away.

Geoff “Hargo” Hargadon, a financial advisor, and Gary Strack, the owner and chef at Central Kitchen are the dual masterminds of the project, which has been several years in the making. “These are mostly people who I have followed over the years and whose work I like a lot,” says Hargo, whose own “Gates of Somerville” art project was an internet phenomenon. “Some of them are emerging street artists while others have already made the scene and have a big following. And others just sort of showed up and wanted to get in on it.”

Elsewhere on the mural, Dan Bergeron (of Toronto, Canada), Rene Gagnon (Fall River) and Blake Marquis (Boston) created an artist coating a surveillance camera with spray paint. Next to it, they stenciled Picasso’s mantra “good artists copy, great artists steal.” Further down, Boston-based Kenji Nakayama and Buildmore drew themselves on the wall making their own wall, in full simulacrum mode. Stickers of Edie Sedgwick, Andre the Giant, Bowie, the Monopoly Man, even Phoenix Adult Entertainment ads and soda wrappers are just a few of the elements floating around inside the giant montage. “Painting the flower was a no-brainer,” says New York City’s Michael De Feo of his contribution. “For the wheat-pasted paintings, I simply loaded my trunk with work and made some selections while I was there.”

“I like the open dialogue of the street,” says Strack. “It’s not like the gallery is ignoring this style. But the gallery gets stagnant really quickly. These guys are circus performers. It’s big and dramatic and really sexy.”

Strack worked hand-in-hand with the mayor’s office on the project. “Mayor Reeves is a pretty hip guy, so he was down with it,” he says. Being that he owns the building, the main reason he even contacted the office was to insure Public Works didn’t mistake the piece as actual graffiti and paint over it.

“The wall is true in spirit,” says contributor Celso (of the Endless Love Crew), “but the best work to me is the stuff that people are willing to go to jail for. It’s more of a rush when you are painting in the dark, watching your back and trying to finish a work before the cops arrive.”

Hargo admits that something may be lost from a “legitimate” mural of street art, “But,” he says, “we tried to put it together in such a way that it wasn’t quite as tidy as a gallery. Many decisions were made by the artists on the spot based on space constraints, some guys went over others — like what happens on the street — and in some cases feathers were ruffled. But in the end everybody realized that’s the way it goes with street art.”

For his part, Boston-via-Philippines artist Bren Bataclan spreads love with his trademark cartoon-inspired grins. Despite this being his first “true” street-art project, his simple philosophy extends to The Wall. There he pays homage to Central Square, where he launched his art career. “That’s why I included the word ‘salamat’ on my piece,” Bataclan says. “It means ‘thank you’ in Tagalog.”

The public art also remains true to its roots by striving to reach a much broader and more general audience, something not necessarily guaranteed in the confines of a gallery. But it also means that the mural is temporary and will be subject to the elements and decay. “These spaces usually have a lifespan,” Strack says with a laugh.

“This is the largest legal collaboration like this that I know of and I hope not the last,” says Drew Katz of Gallery Katz. “A project of this magnitude is clearly a first and long overdue.” Other artists include names like Boston’s 5003 and DDock, Baltimore’s Gaia, Seattle’s Heck, and New York’s Plasma Slugs, Siren, Phallic Mammary, Billi Kid and the Endless Love Crew collaborative.

The Wall stands opposite Central Square’s historic photomontage, and very much in contrast with the area’s other murals depicting diverse peoples sharing a potluck and experiencing life at peace with each other. “There is something irreverent about street art,” says Hargo. “And some of it is funny. But it can also be dark and serious and angry.”

“Central Square is one of the most lively and real places in Boston,” he says. “Pedestrian traffic is high and its demographics are mixed in many ways. I don’t want to get into a whole ‘which side of the river is hipper’ argument with anyone. But, I’ll just say that if I could have pointed my finger at any location in the Boston area for this installation, it would have been right there.”

Thanks to a hip mayor, two street-art connoisseurs and 20 of the best artists of their kind anywhere, that’s exactly where it’s at.