The National Portrait Gallery's first piece of public art, the enigmatic orange Geo Face Distributor, is an intriguing take on portraits

Nor is it the rarefied contents of particular buildings that viewers must enter to see, such that they might contemplate the artworks in correspondingly distinguished surrounds (although it is a close relative).

Rather, public sculptures are manifestations of artists' creative expression, plucked out and planted directly in spaces accessible to all.

Canberra has certainly embraced the medium of public art, with myriad examples featuring throughout the city.

And when travelling through Canberra's culture loop, and taking the opportunity to explore the stretch of national institutions along the southern shore of Lake Burley Griffin - that deliberately curated space, book-ended by the bridges - there are some excellent specimens to investigate.

Some of these sculptures speak particularly to their immediate environment, the landscape in which they are placed; some are fine examples of art-historical periods and styles, alternating between reflecting and pushing back against their modernist and late-brutalist architectural backdrops.

And then we come to the National Portrait Gallery's first foray into the domain of public sculpture.

Situated at the entrance to the Gallery, James Angus' Geo Face Distributor is a visual beacon on approach; depending on the direction you are coming from, it catches your eye from quite a distance.

At first glance it's large, bright orange, and luminous - an amorphous splash in gently toned man-made surroundings.

Located in Old Parliament House for the first decade of its life, the Portrait Gallery moved to its purpose-built permanent home by the lake - adjacent to the High Court and the National Gallery of Australia - in 2008.

Commissioned to celebrate the building's launch, how then does Geo Face Distributor inform the notion of Australian portraiture?

The sculpture unapologetically inserts contemporary abstraction into the territory of what is often considered a traditional, representational realm.

The work is a dramatic intervention, disrupting both its physical setting and, in a contextual sense, its institution, as it takes its place within the national collection of portraits.

And what of public sculpture's audience, drawn from the broadest demographic imaginable; some will be art aficionados, able to confidently place styles and movements, while others will be enthusiastic explorers, keen to see what there is to be seen, without necessarily wielding a textbook knowledge of the arts.

What might either group make of this abstract sculpture installed at the entrance to the nation's gallery of noteworthy Australians?

James Angus can help with that. In contemplating his creation, the artist says that as you look, "The faces emerge: cavities link up to form pairs of eyes and mouths, protrusions start to look like noses ... I'm hoping the sculpture will create a pushing and pulling of faces".

Going on to explain the title, he notes, "Geo" refers to the use of geometry to create the surface of the work. It also implies geography and the topography of the earth. "Face" is obviously a prompt for the process of figuration, and "Distributor" refers to the process of mapping those faces onto the sculpture.'

Having this information from the artist on board makes it easier for us to engage with the work, much like being given a clue to a mystery: there are no guarantees that you'll solve it in the end, but you come equipped with a tool to help you in your investigation.

This freedom of looking, hunting out the hints of facial features, gives the viewer almost complete agency over how the work might emerge as a recognisable face. There is no 'right' answer, with each individual experience likely to be quite different from the next.

In this sense one could propose that it's an extreme instance of the critical importance of the viewer - where the audience is absolutely essential in order to bring awareness, understanding, and context to the artwork.

Does this work encourage viewers to reflect more profoundly when viewing portraits - to explore them more thoroughly?

Hopefully it leaves an echo of remembrance, a new or sharpened instinct to take a longer study when wandering through this particular building's rarefied contents, to be contemplated in their correspondingly distinguished setting.

With the commissioning of this sculpture the National Portrait Gallery sought to broaden ideas around what it means to recognise and depict the individual; to encourage discussion around looking and interrogation; and to reveal the character and the essence of the familiar that is there to be found within the faces of Australia.

When you get the chance, spend a little time in the company of Geo Face Distributor. I believe that both the Gallery's ambition and the artist's intention for our shining yet enigmatic beacon have truly been met.