At Redwood City Qt Developer Days (also where, BTW, a bunch of KDE geeks made a funny group photo), I started a tradition: throw an idea for a demo and I will implement it for the talk. The challenge for my graphics talk was the subtle effect in the Android's home screen. We saw T-Mobile G1 the night before and recalled again the good old games in the eighties. So the next morning I waked up earlier both to rehearse my talk (again) and to implement this parallax sliding. It turned out to be almost trivial to implement (200 lines of code) so just check it out!