Well, clever ones, actually. Using the internal motion sensor.

Finally, they have the technology to do what I think would be a really cool piece of software, for those of us with nostalgia for sixties childhoods--a virtual Etch-a-Sketch. If you decide you don't like the picture you drew, just turn the thing over and shake it to clear the screen.

There actually is one on line, if you want to play with it. Kiss your productivity goodbye today.