Seventy-year old London artist Phyllida Barlow, whose monumental constructions, Phyllida Barlow:tryst, are now at the Nasher Sculpture Center, has a contagious, easy laugh. She delights in the unexpected. “I wouldn’t want my works to be objects of despair.” she says. ” They should be hopeful.”

This joy of surprise overtakes us immediately at the Nasher. We are dwarfed by circus elephants. Or tree houses? They look like wooden AT-ATs, those four-legged, armored things stomping through Star Wars. Or are they just a “heap of stuff?” — as Barlow has called them. The “heaps” that greet us — untitled: stiltedcrates — are large, open boxes teetering on bolted, paint-splattered stilts, some reaching within inches of the famed Nasher roof. That’s one way to block the sunlight reflected from Museum Tower. But navigating the space in between and underneath these raggedy structures causes some timidness — and smiles.

Eye-level viewing doesn’t interest Barlow. So she builds big. She builds high and low. She demands we move through space differently. Look up at the “backstage,” as she calls the infrastructure, and experience this theater’s “frontstage” as well. But always look up, down, sideways and forwards as we do.

“It would be wonderful if people could crawl on all fours to look at sculpture differently,” she says. “Sculpture demands our attention at 360-degree angles.” The views that surprise us hold the mystery, which is why Barlow punches holes and leaves windows, inviting us to peer inside. She is fascinated with things that aren’t finished. They have a “certain sublime beauty.”

Although entranced, we move cautiously around those works which loom above us and around us and those which appear ready to tumble over. In the lower level gallery, we walk tentatively through a brightly-colored maze and tangle of banners. It’s like Christo’s famous “The Gates” — the series of a thousand, dangling, orange panels lining a pathway through Central Park — only here, they’re dense and crowded together, with no clear path to follow, we can’t see very far forward. It’s the most physically challenging and playful use of the gallery since Martin Creed’s No. 1190, half the air in a given space — the popular ‘balloon room’ — in 2011. We are either in a celebration or a protest march. Whichever it is — if we are not engaged, aware of where we are, where to go next, how to find the exit door, we will trip.

Barlow’s work dares us to come closer. She teases us with “what if?” She toys with our imagination, tempts us to touch, and then says we can’t. “The longing to do,” she says, “is more exciting than the actual touch.”

In the second gallery, untitled:hangingmonument is like some massive tree root of foam, wood and wrapped fabric dangling from a steel beam. It could easily sway with a gentle tap ( as Barlow demonstrated). She insists upon it remaining immobile. “The possibility of movement is more exciting than the movement itself. The audience [walking around it] agitates it.”

The work may be static, but its unconventional placement and visible state of flux or ‘unfinish’ exhibit a restlessness. With scattered, trailing elements and space-invading projections and piles, they look unplanned — they seem to have just been left there. And the fact is none is permanent. Most of the everyday materials — lumber, plywood, plaster, cardboard and cloth — will exist joined in a “tryst” for only the next three months at the Nasher. Trysts, after all, are temporary. Brief, memorable meetings. Much will then be recycled and re-purposed to reinvent other trysts.

New constructions will rendezvous in new venues putting  others in risky yet rewarding situations.

Phyllida Barlow runs at the Nasher through Aug. 30.

Guest Blogger Gail Sachson owns Ask Me About Art offering lectures, tours and program planning.