Today's smartphones all seem to share the same silhouette. You'll find a large, flat touchscreen on the front, and maybe a few buttons across the bottom. The form factor will be thin enough to fit in your pocket, and it might include a slide-out QWERTY keyboard. Snooze. But it doesn't have to be that way, as futuristic cell phone concepts constantly remind us.

At the Nokia World Conference in London -- the location where Nokia's Windows Phone handsets made their debut -- a new flexible handset was being demoed. It's called the Nokia Kinetic Device and, yes, the entire phone is being flexed in the photo above.

The entire device is made of plastic, right down to the AMOLED display on the front. Rather than using swipes and pinches to navigate the UI, you would use bends and twists. To zoom into a page, you bend the phone so its center buckles towards you; zoom out by doing the opposite. A twisting action is used to scroll through photos or adjust the volume.

Since it is all plastic, and all bendy, the prototype lacks a number of features that would allow it to be a true smartphone -- or even a cell phone, if we're being honest. The touchscreen isn't capacitive, there's no camera, no GPS and no actual phone functionality. We said it was a prototype, right?

So it clearly has a way to go before it starts landing in consumer hands. Here's a collection of eight other concepts and protypes that push cell phone design to the limit.