Harfleet and Turtle Sarten started with 10, spending winter learning how to connect pallets together and how many they would need to build a 30m x 23m structure. There's been constant checking during the install to ensure the construction is exactly as planned.
One pallet just centimetres out of place could mean the structure doesn't work as it should.
"It's involved a lot of problem-solving but it's a bit like making something out of Lego," says Harfleet.
While this may be their most ambitious work yet, they've made many large scale artworks for outdoor sculpture shows, galleries and at community events which prove the truth of the expression seeing is believing.
At 2016's Sculpture OnShore, they won the People's Choice Award for Max and Bella and friends which used 10,000 white pinwheels to represent the 5 per cent of NZ adults experiencing psychological distress, like anxiety and depression, each month.
"When you talk about those numbers, it's hard to get a sense of what that actually looks like but we like to provide context with our work. We'll research something and then create a visual which gives a sense of the scale. Seeing 10,000 pinwheels gathered together communicates more than just hearing a number."
But they don't just make art; the couple frequently become involved with the causes they're highlighting. In 2014, they strung 6000 plastic lunchboxes from trees as part of the Feed the Kids Too project, which later saw the 7500 low decile students gifted lunchboxes and lunch.
Then there's Give a kid a blanket started in 2015, after the couple were shocked when a coroner's report stated that a cold, damp house contributed to the death of a 2 year old girl. They launched a community art activation, photographing people who donated blankets – 1273 in that first year - which were then given to those in need. This year's Give a kid a blanket handed out 17,469 blankets, duvets, sleeping bags and baby sleep sacks. The figure doesn't include new pillows, socks, beanies, pyjamas, new hot water bottles, warm clothing and additional bedding.
"It's about having a platform to talk to people about how things could be changed," says Turtle Sarten. "Even if it's just for a small moment that someone stops and pays attention, that's still something."
•NZ Sculpture OnShore is at Fort Takapuna from Saturday November 3 – Sunday November 18. It includes a wide-range of contemporary sculpture by some of our leading practitioners with funds donated to NZ Women's Refuge.