I suppose it was this bottom left swipe I was really picturing, and I will admit my experience of iOS colours my enthusiasm for invisible bits of UI in general.

I suppose it was this bottom left swipe I was really picturing, and I will admit my experience of iOS colours my enthusiasm for invisible bits of UI in general. I can accept it's possible to have a small pool of gestures and still allow users to build a strong, consistent mental model of how to interact with a device.