Zhang Yue likes to think big.
His grand vision: to build the world's tallest tower. No regular skyscraper, but a 'vertical city' with schools, hospitals, indoor farms and lush gardens under one roof; an energy-efficient ecotopia for 30,000 pioneering residents; and a giant experiment in commute-free urban living that stands distinct from China’s polluted, more conventionally horizontal, metropolises.
Not impressed yet? According to Zhang, the 220-floor skyscraper would take only three months to assemble. “You just have to build the tallest,” he says. “Only then will people notice and remember, and spread your philosophy.”
If completed, Sky City would soar 838 metres above the city of Changsha.
But in the two years since it was announced, not a single girder has been placed. The project has instead wallowed in permit purgatory. Not everyone is convinced his idea is practical or safe, and the government has reportedly been cautious about greenlighting such an ambitious structure.
That said, Zhang's dream might now be inching closer. Apartments are soon to go on sale in Sky City’s little brother, Mini Sky City, according to reports.
This is the rather blocky, 57-storey tower which received a flurry of coverage in early 2015 after it shot up in just 19 working days. The 204 metre building was assembled at a speed of three storeys per day, thanks to its unique construction technique: it was made in a factory.
Thousands of steel modules were pre-fabricated on a production line and then slotted together onsite like oversized Meccano. These steel structures have the crucial combination of strength and flexibility, says Zhang, making them more quake-proof than their concrete cousins.
Questions remain for some about whether this model could be scaled up to something four times the size. But for Zhang and his company, Broad Group, the hope is that Mini Sky City can capture the imagination and prise open the wallets of the Chinese public, paving the way to their loftier ambitions.
I spent a good deal of time with Zhang Yue while filming a documentary about his buildings for the BBC. He's wiry, fiery and feisty, with an infectious enthusiasm and unyielding gaze. And his presence is felt everywhere around the company HQ, Broad Town.
It’s a world unto itself, a square kilometre of parkland tucked away from the bustle of downtown Changsha. Statues of 'great thinkers' such as Plato, Li Bai, Coco Chanel, Deng Xiaoping and Napoleon loiter heroically between finely manicured hedges. As the morning mist is burnt away, staff dorms and hangar-like factories are revealed, from which blue-overalled workers file towards the canteen for bowls of spicy Hunanese cuisine. The food is almost all grown on organic farms on campus.
At the centre of Broad Town stands a palatial building with echoes of Versailles. This is in fact Zhang Yue’s 'Environmental Philosophy Institute'. Cultivating a deep respect for the environment, it turns out, is central to life here. And Zhang Yue is their philosopher king.
All workers are required to memorise his handbook "Life Attitudes of an Earth Citizen", detailing how to live a sustainable life. Company culture means no waste, with fines for those who fail to finish their food. Trust is important: there's no attendant at the campus shop; staff simply swipe work passes to pay. And all new recruits have to don green fatigues and go through a week's military-style 'boot camp', designed to test mental fortitude.
Zhang says: “In the whole of Broad Town, two people are most important – one is me, the other is my wife. She does all the arty things around campus. I do everything environmental.”
But if you ask him nicely, he'll show you one of his own early oil paintings. For Zhang Yue started as an artist himself. "Good Dream" shows a young Zhang Yue leaning on the edge of his bed, head held in a muscular arm.
"That was the best time. All we had were fantasies. All we had was ourselves," says Zhang. "Now what we think of are problems of the world."
It was painted in 1988, the same year Zhang Yue entered business. He taught himself engineering, and built his company up selling energy-efficient boilers, air conditioning and air purifiers. In the early 2000s he was one of his country's very richest, and became the first Chinese citizen to own a private plane.
Now, though, he prefers to be thought of as an eco-entrepreneur, and his aircraft gather dust.
He launched his company's construction wing, Broad Sustainable Building, after being shocked by the collapse of so many poorly-constructed homes and schools in Sichuan's 2008 earthquake.
Fast forward seven years and Broad Group have completed some 30 buildings using their modular technique, with timelapse videos showing the phenomenal speed of their construction widely viewed online.
But the Sky City building site still stands empty. Recent reports show the land surreptitiously used by local farmers as fishponds and vegetable patches. Broad Group themselves remain tight-lipped on the exact reasons for the delays, and several commentators have written the whole thing off as an elaborate publicity stunt.
Some may sense the spectre of Dongtan. The proposed eco-city on Chongming Island, planned to be a home for half a million people, was plagued by political machinations and corruption. Billed by engineering firm Arup as "the quest to create a new world", the project withered and few signs of the grand green plans are evident today, other than a few giant wind turbines.
Julie Sze, associate professor at the University of California, Davis, says in her book Fantasy Islands that in its failure she saw what Chinese "eco-dreams and fantasies are made of" – that amongst all the fanfare, the emphasis on the grand scale and top-down approach heralded its demise.
But Zhang Yue is not a man who is easily fazed and is resolute that the tower will be built "this year or next year". Just recently the government of Hunan showed explicit support for Broad Group's modular system of building.
And if it does get built, that's when the real work would begin. Zhang's senior managers tell me that they want to shake up the whole construction industry, and they plan to "dominate 30% of the market in the future".
But first, says Zhang, "we have to effectively, broadly, quickly change people's thinking".
"We have to do something spectacular."