By providing an open platform for the creation of augmented-reality layers, these apps have democratised the AR industry - and made possible flights of fancy such as Unseen Sculptures, in which new-media artist Warren Armstrong and nearly two dozen others collaborated to populate central Melbourne and Sydney with a range of virtual artworks that "appeared" when smartphones running the Layar app were pointed at particular parts of the city."I'm fascinated by mobile devices and their ubiquity," says Armstrong, who has spearheaded the project's expansion - including planned engagements with the Sydney Fringe Festival, Cairns Festival and other projects. "It's very immersive: you can go to a location, put on headphones and do amazing things with sounds. Layar takes care of the fiddly back-end stuff for people who aren't au fait with PHP or MySQL programming. The whole thing is in its infancy, and there's a lot of scope for creating new things."