To our minds, Lieberman's piano is one of the most interesting offerings at the Google-sponsored DevArt exhibition, which opens at the Barbican in London tomorrow. The show is all about "art made with code," so its fitting that the amount of programming involved in Lieberman's project is relatively huge. Servers in the cloud decode and analyze hundreds of live MP3 streams, looking for sounds that match the pitch of a musical note. When someone plays the keyboard, these notes are then recoded back into MP3's and played through a 360-degree speaker array, so that the direction of the sound matches its geographic origin relative to where you're standing. Sound complicated? In practice, it's actually very simple -- and also strangely rewarding, especially when you hit an unexpected chord, like a classical cello recording mixed with an Islamic call to prayer and a Greek DJ yelling about something unintelligible.