Scientists from MIT Media Lab have created a shape-changing wearable device that they call LineFORM [mit.edu]:
We propose a novel Shape Changing Interface which has the form of a "Line". Lines have several interesting characteristics from the perspective of interaction design: abstractness of data representation; a variety of inherent interactions / affordances; and constraints as boundaries or borderlines. By utilising such aspects of lines together with the added capability of shape-shifting, we present various applications in different scenarios such as shape changing cords, mobiles, body constraints, and data manipulation to investigate the design space of line-based shape changing interfaces.
Via NextBigFuture [nextbigfuture.com]:
LineFORM starts with a line; a linear series of actuators that can move independently or together to arrange itself in new shapes [tumblr.com]. In one demo, it's wrapped around a wrist like a high-tech Slap Wrap. In this configuration, it's able to convey a notification through haptic feedback, uncoiling its end and gently tapping a user's wrist. Its creators ask us to imagine this forming the core structure of a mobile device, presumably replete with a display, microphone and speaker. On receiving the notification, the user then unfurls it, and it contracts into a rectangular prism. After he taps away on an imaginary display, it shape-shifts into an old-timey telephone.
There's also the potential for LineFORM to act as an intelligent cable. Such a cable would be capable of recognizing a number of modules, [engadget.com] transforming where necessary. On recognizing an attached light bulb, the robot jolts into action, almost-instantaneously becoming a posable lamp, complete with three-dimensional dimmer switch.
LineFORM: Actuated Curve Interfaces for Display, Interaction, and Constraint [mit.edu] [full paper]