In 1976 Ryan McNaught was a small boy growing up in Melbourne when his grandma, Hazel Smith, went to Coles and, for 29 cents, bought him his first Lego set.
Seated at the foot of his grandfather's chair, McNaught didn't worry that it was pouring with rain outside; instead he contentedly built a small boat and his love for Lego was launched.
From then on, he received Lego for most birthdays and Christmases and never tired of tinkering around with the plastic bricks. But even Hazel may be surprised at how far her grandson's creations have grown.
He's now one of only 14 Lego Certified Professionals in the world - and the only one in the Southern hemisphere - and is responsible for one of Auckland's most novel, and tallest, Christmas attractions.
It's a 10m tall Christmas tree, complete with kiwiana-themed decorations, which will stand in Aotea Square until December 27.
Easily the tallest model McNaught has made, it includes 450,000 bricks - a mix of bigger Duplo and traditional Lego - and weighs in at 3500kgs.
The father of twin boys says the tree has been displayed in Sydney and Melbourne, but he and his team added a Lego rugby ball, some curious Kiwi, a pukeko and a sacred kingfisher to give it a more local look.
The actual build took McNaught and six assistants 1200 hours, but he says the most successful Lego projects start long before you even pick up a brick.
"It begins with research because you have to know your subject and the more you know and understand about it, the better your model build will be," he explains. "I'd say 25 per cent of your success depends of doing that research."
Next up is to sketch and sketch and, if you have to, sketch some more so you've got sound working drawings. The Lego Christmas tree, with a hidden trunk of steel, was mapped out on computer and had to meet the requirements of structural engineers.
It can withstand gales and although no child has ever tried, McNaught says climbing the tree would be unlikely to destabilise it. Not that he's encouraging anyone to try it.
"Then you build it in sections, you compartmentalise and built a bit at a time."
He says each project presents different challenges; the Christmas tree ones centred round the logistics of transporting such a heavy model.
"It was quite something to see guys who usually work in construction having to use a crane to put Lego in place."
A former software developer and chief information officer, he was recruited by Lego after he developed software that let kids use their iPads to create robots from Lego Mindstorm kits.
McNaught and his Melbourne-based team have since built some of the world's most detailed and largest Lego models: a larger-than-life Lego copy of the Mona Lisa, the Seven Ancient Wonders of the World, numerous film characters and hundreds of models for museums and art galleries.
"It was the third happiest day of my life when I walked in and told my boss I was quitting to go and play with Lego," he says. "You can't really have a bad day when you're making things out of Lego; a bad day for us is when the bricks don't go together in the way we want but you imagine what a bad day is like for, say, a nurse. There's no comparison."