A Swiss troupe's daring aerial stunts on a gigantic rotating Meccano-like apparatus has become a spectator favourite.
öff öff Productions are wowing the public this summer at the Zurich Theatre Spectacle, an annual festival on the banks of the lake.
The troupe has been together since 1994, but their unusual dance, acrobatics and climbing combinations are difficult to classify.
A recent performance involved dizzying moves off an iron bridge in Bern, witnessed by 17,000 people.
But the creation of a customised "air station" and its complex demands has ushered in a whole new era for the three men and three women who make up öff öff Productions.
Because the air station is transportable, the troupe is no longer bound to a fixed locale and can tour for the first time.
Performer and artistic director Heidi Aemisegger had been mulling over how to do "air dancing" for years.
With the exhilaration of "bridge dancing" still fresh, the members began brainstorming how to take to the road. The result was a competition for builders and artists.
A retired engineer was brought in to oversee construction of the winning entry, the air station. "He had built more than 70 cranes in his life," Aemisegger told swissinfo.
Made up of a customised steel tower with two asymmetrical slowly circulating "wings", the air station stands an imposing 17 metres high and weighs a hefty 4.5 tons.
Ladders make it possible for artists to climb, dance and hang from all over the air station.
This is the first time that the performers have done such a show. "It's a new challenge to move on an object that is itself moving," says troupe member Pascal Siegrist.
Fiona Hirzel, who has a background in classical ballet, says she feels "at one" with the framework. "But when I come down, it's like coming off a boat. I can't stand straight."
As soon as one of the performers moves, both "wings" are put in motion, with the result that each individual movement affects all six dancers. All team members are therefore hugely dependent on each other.
"This dependency has an inherent danger, just like in real life. If I'm inattentive, I can put one or more performers in a very critical situation," said Aemisegger.
For this reason there needs to be precise coordination of the six members who are hanging off and moving around the imposing air station.
To guard against accidents they are secured with safety harnesses like those used by mountain climbers.
As if it were not enough to simply perform on the air station, the artists are also responsible for taking it apart and putting it together.
"It builds trust to see how it's constructed and how it functions," says Hirzel.
Aemisegger sees advantages in being able to repeat the same performance over and over, something the troupe has not been able to do in the past.
"When you perform a piece over 60 times, it gains in maturity. You can really fine-tune it."
In October, öff öff Productions will be at the Biennale in Venice, a leading contemporary arts exhibition.
Next year the troupe plans to perform in French-speaking Switzerland and later in nearby countries.
Siegrist is enthusiastic about the troupe's new direction.
"I've been a passionate climber since I was 12 and I've been dancing intensively since I was 20. It's so unusual to actually be able to combine these two passions."
The prospect of travelling around in a caravan also appeals to the artists.
"Actually, I didn't want to be a ballet dancer," says Hirzel. "I wanted to be a circus artist. With this production I feel like I'm returning, after many detours, to my origins."
The air station is 17 metres high and weighs 4.5 tons.
It was dubbed "air station" in honour of a Paul Klee painting of the same name.
The accompanying music was written specially and is mostly live.
There are 65 shows planned for air station tour, which runs from June 10 to September 25.
The group will be at the Zurich Theatre Spectacle from August 18-21.
(Adapted from German by Kathleen Peters), swissinfo.ch