and be able to compute state information, possibly with assistance from each other. Fundamentally, catoms consist of a CPU, a network device for communication, a single pixel display, several sensors, an onboard battery, and a means to adhere to one another. Current catoms The researchers at Carnegie Mellon University have developed various prototypes of catoms. These vary from small cubes to giant helium balloons. The prototype that is most like what developers hope catoms will become is the planar catom. These take the form of 44 mm diameter cylinders. These cylinders are equipped with 24 electromagnets arranged in a series of stacked rings along the cylinder's circumference. Movement is achieved by the catoms cooperatively enabling and disabling the magnets in order to roll along each other's surfaces. Only one magnet on each catom is energized at a time. These prototypes are able to reconfigure themselves quite quickly, with the uncoupling of two units, movement to another contact point, and recoupling taking only about 100 ms. Power is supplied to the catoms using pickup feet on the bottom of the cylinder. Conductive strips on the table supply the necessary power. Future design In the current design, the catoms are only able to move in two dimensions relative to each other. Future catoms will be required to move in three dimensions relative to each other. The goal of the researchers is to develop a millimeter scale catom with no moving parts, to allow for mass manufacturability. Millions of these microrobots will be able to emit variable color and intensity of light, allowing for dynamic physical rendering. The design goal has shifted to creating catoms that are simple enough to only function as part of an ensemble, with the ensemble as a whole being capable of higher function. As the catoms are scaled down, an onboard battery sufficient to power it will exceed the size of the catom itself, so an alternate energy solution is desired. Research is being done into powering all of the catoms in an ensemble, utilizing the catom-to-catom contact as a means of energy transport. One possibility being explored is using a special table with positive and negative electrodes and routing the power internally through the catoms, via “virtual wires.” Another major design challenge will be developing a genderless unary connector for the catoms in order to keep reconfiguration time at a minimum. Nanofibers provide a possible solution to