when combined with others, forms an object. Also like a cell, it needs power, programming and a cohesive force. The human cells use energy, are programmed by the brain and bound together by various forces, such as electromagnetism or chemical bonds.

"In terms of the hardware side, we're starting to build prototypes at a couple of different scales -- some very large prototypes that replicate all the computational and other components we want. Those are about two inches across," Mowry said. "And some very small prototypes in the submillimeter realm that are just starting to replicate geometry. We expect, in the coming year, to start to put transistors on those as well, which would give us the computation we need."

If all goes as planned, the team says, one of the earliest applications might be only a few years away. They call it the 3-D fax machine.

Using catoms Goldstein predicts would be a millimeter in diameter -- still very large but functional -- users could capture and reproduce any arbitrary object using a new breed of fax machine, much like a sci-fi teleportation device.

Unlike teleportation, however, the machine would merely duplicate an object as opposed to actually sending it to another locale. Ideally if the technology is perfected, the catoms would be so small they could emulate any texture. But Goldstein is optimistic about the 3-D fax machine, despite its bulkier catoms.

"We have looked at a lot of other applications, and probably the most convincing one to me in terms of both how close it is and also how much work we've done on it, is this idea of a 3-D fax machine," Goldstein said. "The reason that seems so close to me is that you don't actually need to have the thing moving dynamically in real time. The hardware mechanisms you need to build that are fairly simple."

By "dynamic movement," Goldstein means that this 3-D fax machine would not have to worry about duplicating objects that move independently -- instead the replications would be stationary, inanimate things.

The catoms -- the hardware -- are one of the two primary challenges of making dynamic physical rendering a reality. The team believes that building the catoms is, while certainly a tremendous engineering challenge, "eminently doable." In fact, Campbell recalled, the first great leap forward from mere idea toward reality was when they got a prototype to move.

"It took off dramatically when the very first prototype wiggled -- which was still very far away from a working catom -- and we were able to show that to people. We then got the interest of a lot of faculty. Then suddenly the project grew significantly in terms of the number of CMU people involved. Another big leap was when the project became not just a CMU project, but an Intel project as well. In the last year, we've made a fairly huge amount of progress."

The team has made some advances on the hardware side, experimenting with various adhesive forces such as electric fields and electromagnetism. Currently the researchers say that electric fields hold the most promise on the scale of microscopically rendered objects. The challenge is conducting experiments on a microscopic level to confirm their suspicion. Such experiments are difficult and costly.

Regardless, the team is quite confident that, with the "proper investment," the catoms can be built. If anything derails the project, it won't be building the catoms, it will be designing the software. The software will be the brains of an object, telling each catom how to move, what color light to emit, what arrangement will result in the proper texture, among other variables.

If the object were a human replica, the number of catoms the software would command would be in the

Chad Vander Veen  |  Editor, FutureStructure

Chad Vander Veen is the editor of FutureStructure.com