The dictionary says that a “figment” exists only in someone’s imagination, but producers of this weekend’s FIGMENT Boston disagree.

This free participatory arts festival is totally tangible: one might even go so far as to say it strives for “the ultimate in tactility.” Whereas many indoor art galleries have signs warning, “Do not touch,” FIGMENT says “Feel free to grope.”

As Jason Turgeon, the producer who brought FIGMENT to the Hub from New York, explains, “We want people to break down the walls between art and the viewer. So we don’t have viewers, we have participants.”

This Saturday and Sunday (July 30-31), FIGMENT Boston returns to the Rose Kennedy Greenway for a seventh serendipitous year to transform the mile and a half of urban greenery into a family-friendly network of collaborative artwork and surprises.

Dozens of whimsical do-it-yourself arts stations beckon from between somewhat more permanent art installations like the monumental bronze animal heads representing the twelve signs of the Chinese zodiac by international superstar Ai Weiwei.

FIGMENT Boston is part of a national FIGMENT festival community. Founded in 2007 on New York City’s Governors Island with a handful of projects and a few thousand enthusiasts, FIGMENT expanded the next year to its first satellite city, Boston.

The concept has grown exponentially into a multi-day, multi-city series, along the way adding along the way spin-offs ranging from North Adams here in Massachusetts to big cities like Toronto and Chicago, even as far away as Derby, UK. In each of these cities the local all-volunteer staff seeks to “remove the barriers of museum and gallery walls and entrance fees, blurring the lines between those who create and those who enjoy art.”

To fund this and other FIGMENT Boston events like its First Night installations, Boston artists generously auction off art works to raise money, among them Uphams Corner’s Franklin Marval, who this year donated his painting “Guitar with Heart.”

So what kind of art installations are we talking about?

Many of the 2016 options are easy to understand and sound innocent enough. “Bubbles for everyone” “One hundred and fifty interactive synchronous fireflies,” “Middle East Belly Dance Show,” “School of illuminated fish that glow and move in response to an electronic ocean” and “Come rub our giant Genie Lamp to have your wish granted with a giant poof of smoke and lights!”

But, your guess is good as mine about what goes on in the “Automatic Subconscious non-geodesic Dome” or “the Slo-Mo Zone, the High Five Zone or the Silly Walk Zone.”

Would you dare to “Crank the three letter-pressed fabric text cut-up scrolls to receive your own anthropomorphic message”?

At the very least, your vocabulary should get a big boost from investigating all these intriguing outposts.

For further details, visit boston.figmentproject.org. Saturday hours are 11 a.m. to 11 p.m., including the FIGMENT After Dark dance parties. Sunday hours are noon to 6 p.m.