(Reuters) - They look vaguely like miniature hockey pucks skittering along on three pin-like metal legs, but a swarm of small robots called Kilobots at a laboratory at Harvard University is making a little bit of history for automatons everywhere.

Researchers who created a battalion of 1,024 of these robots said on Thursday the mini-machines are able to communicate with one another and organize themselves into two-dimensional shapes like letters of the alphabet.

Much smaller groups of robots have been able to carry out similar tasks, but never a group this size.

The Kilobots are told by the researchers via an infrared transmitter to do a certain job. The robots then do it collectively without further input from a human being.

In a study published in the journal Science, they formed themselves on a large tabletop into the shapes of the letter "K," a star, a solid square and a wrench.

It may be a step forward for collective artificial intelligence, although the researchers acknowledge the Kilobots are not exactly thinking deep thoughts.

"This is a 'collective' of robots - a group of robots that work together to complete a common goal," said Harvard computer scientist Michael Rubenstein, who led the study. "If you call collective artificial intelligence the ability of a 'collective' to start to behave as a single entity, you could call this collective artificial intelligence."

The Kilobots are simple and inexpensive robots built to talk to fellow Kilobots and sense the location of those others using infrared light. They use vibration motors to slide across a surface on their three legs.

But the surface must be very smooth. The one used in this study was essentially an eight foot (2.4 meter) by eight foot "dry erase" board tabletop. Even minor surface friction like that of paper halts them.

The robots measure about 1.2 inches in diameter and two inches tall. The material to build each of them cost just $14.

Rubenstein said the research anticipates a day when people may send many robots acting as a single entity to perform a task - perhaps to a destination like Mars - instead of humans or a single robot.

A "collective" may better handle an unknown environment - for example, forming into a snake shape to navigate sand dunes or like a ball to roll down a hill. He said a "collective" also is "fault tolerant" - if a single robot among 1,000 breaks down, plenty are left to do the job.

The Kilobot name is a play on the word kilobit, meaning 1,024 bits of digital information. But to some it might sound menacing - as in "killer robot" - as if it belongs in a movie like "Terminator 3: Rise of the Machines."

"I tell people that these robots are not very dangerous. The only way that they could hurt you is if you try to eat one. They can't even go over a piece of paper. So they're kind of stuck where they are," Rubenstein said.

(Reporting by Will Dunham, editing by G Crosse)