If you take a walk around Glebe in inner-city Sydney you'll likely encounter sporadic piles of rocks, some resting atop others at surprising angles.
These gravity-defying sculptures are the work of Anthony Jucha and his three children.
"It's satisfying if you set up something pretty," Mr Jucha says. "Unless it keeps falling over," his son Kasper, 12, interjects. "Yeah, that's not relaxing. That can be frustrating."
That doesn't happen too often for Mr Jucha and Kasper.
They became world champions earlier this month in the niche, but intense sport of rock stacking.
Held at the annual Earth Art Festival in Llano, about two hours west of Austin, Texas, the rock stacking world championships pushes participants to achieve new heights, literally, in the relatively new sport.
With 31 rocks stacked together in 10 minutes, Mr Jucha set a new world record to claim gold in the quantity category.
"With quantity you want sort of pancake rocks, you know, quite flat things," he says.
Mr Jucha also broke the record in the height category, but another competitor went on by even more, reaching 2.5 metres.
In the balance event, participants were given the same dozen rocks to balance as many as possible in three minutes, with added points for degree of difficulty and artistry.
Kasper beat the adults, including his own father, balancing eight stones in an improbable structure.
"I kind of knocked it off in a minute because I forgot everyone was there and I just did something like this and stacked it up in a minute," he says.
Photos of the event show onlookers with their mouths open in awe.
"He was the star of the festival after beating all the grown-ups," proud father Anthony says.
How does it feel to be a world champion? "Normal," Kasper says, back at the Glebe creek bed.
Few people know what rock stacking is, with just a handful of people in Australia who take it seriously.
"Do you think it's ridiculous?" asks his dad. "A little bit," Kasper smiles.
Mixed reactions
A woman passing by with two children stops to admire their handiwork near the footpath.
"Do you use superglue?" she asks. "No, just a steady hand," Anthony responds.
Kasper demonstrates moving a rock around until he finds its centre of gravity.
"When you get it exactly in the middle, it just stays up," he says.
Not everyone is a fan though. Some accuse those creating piles of rocks, known as cairns, of disturbing nature.
In 2018, ABC Hobart asked "Yes we cairn or no you can't?" as Tasmanian bushwalkers debated whether the increasingly popular practice was impinging on nature and leading people off the track.
At the end of the Llano festival, which also celebrates rock stacking as an artform, the sculptures created by participants are often destroyed.
"There are members of the community who don't like [and] are a bit freaked out by this sort of hippie convergence in Texas, and will come and trash the art installations after the festival," Mr Jucha told ABC Radio Sydney.
Mr Jucha is OK with that. Whether it be a strong gust of wind or an angry local that brings them down, rock stacks are not made to last.
"It's a ephemeral art, right? … That's kind of part of the deal."
Others just think it's a bit weird. Mr Jucha, a barrister by trade, was cautioned by a colleague not to mention it as it wasn't "very serious looking".
"I think on balance I'm going with it … rock stacking is hardly the weirdest thing that a barrister has ever done," he says.
Self-described 'rock snob'
Mr Jucha's fascination with rock stacking began three or four years ago while taking the family's dog for walks at night.
Then a camping trip to Ulladulla near a river really got him hooked.
"River rocks are the best … because they'll be smoothed off and aesthetically pleasing," he says.
He lay awake one night thinking about an especially impressive stone.
"I thought, 'I've got to have that rock'," he says.
But when he went to fetch it the next day, it was gone.
He later discovered another woman had taken it, but as she was carrying it back, she fell and broke her leg.
"Maybe it was cursed," he says.
While medals are nice to have, it's the artistic side that Mr Jucha is most drawn to.
"I would really like just to get two or three or four really pretty rocks and put them together, rather than making giant crazy things," he says.
It demands complete focus. When he's close to finding the perfect point of contact at which a rock will stay, he feels his breathing change.
"There'll be a big exhale, like a noise and breath coming out, like a deeper level of concentration or something," he says.
Now he is a self-described "rock snob", grimacing as he surveys the "rubbish" around him.
Kasper is less fussed. "They're all good."
