MR EUGENE Tan has a grown-up day job designing good-class bungalows and bringing old shophouses back to life.

By night, he indulges in his boyhood love for Lego. Just like his current project - a life-size Lego recreation of manga robot Astro Boy, who does not grow up - the Lego-loving part of this architect refuses to grow up.

The 36-year-old, who is with Richard Ho Architects and is himself a father of three, started building things with these plastic blocks at age four. He is the one behind the volleyball court-size Lego scale model of The Floating Platform now making its way round the island for public viewing.

To build that, he had the help of more than 500 volunteers and half a tonne of Lego blocks - about 200,000 bricks and mini figures to be exact. The scale model has as many seats as the real structure.

During the planning stage, he said, he hit a brick wall in trying to procure some blocks in shapes and colours that had since gone out of production: 'I had to improvise and revise my design using substitute pieces. There was a lot of back and forth. Each day, as I saw the model take shape, I felt more and more shiok.'

His two-storey condo home in Telok Kurau bears signs of his hobby: A recently acquired ottoman, shaped like a giant red Lego block, sits in his den on the second floor; Lego figures sit in a wall-to-wall glass case in this room - cartoon characters Homer Simpson and Marvin the Martian, video game icon Mario of Super Mario Bros, as well as architectural masterpieces such as Fallingwater and the Guggenheim Museum.

He is proudest of the life-size model of a 1950s Vespa scooter, parked in a corner of the room. Built with tan-coloured bricks and boasting red-and-yellow racing stripes, it took a year to plan and another four months to build. 'Having a Lego Vespa parked at home is so much cooler than having a real one, as you just can't buy one like this with money.'

He has also gone into building 2D Lego models - mosaic-like portraits for which he is increasingly known. Last year, he held a solo exhibition of 15 works, including Lego portraits of former prime minister Lee Kuan Yew and Hollywood siren Marilyn Monroe, done in pop art style.

Working in two dimensions poses its own challenges, he said. 'In 3D, let's say you want to build a fire hydrant. All you need is pure red blocks, as the object itself will create its own shadows based on the lighting. In 2D, everything is flat, and it doesn't project its own shadow. So the challenge is differentiating light and dark, getting the colours right.'

It was this realisation that led him to attempt his first portrait - of his wife and son - in greyscale. It remains his most treasured piece.

His adeptness with Lego started early. By the time he was 11, he had won three consecutive nationwide Lego competitions, building everything from space stations to kimono-clad women dancing in a Japanese garden. Lego had invited him to represent Singapore at the Lego World Cup in Denmark - smack in the year he was due to sit the Primary School Leaving Examination.

His dad said no to the trip.

He is still wistful about the missed opportunity: 'I think it was a pity I didn't go, as Lego's cut-off age was 12. But my dad had good reasons. With a good education, next time you can buy all the Lego you want, he told me.'

He has gone and done exactly that.

Besides shaping his career choice, Lego has taught him the importance of organisation. Pointing to a wall of neatly stacked, microwave-safe takeaway containers - all 400 of them - he said his categorisation of the blocks by colour, shape and type began with a childhood frustration of being unable to find certain blocks.

'When you're building and you're in the zone, having to stop to search for a particular piece can really kill the momentum,' he said.

His parents suggested that he sort his growing brick collection and gave him empty ice-cream tubs. The habit of being neat and organised stuck.

These days, he is using Lego to inculcate patience and organisation in his own children, who are aged one to five; on weekends, he works with them to create custom models of the cartoon characters they know.

His dream project: A scale model of Singapore, with its iconic skyscrapers and heritage buildings. He said: 'Some people are interested in exotic places, but I believe you need to familiarise yourself with your own backyard first.'