In a Child's Tiny Bricks, the Logic of Computers

By Edward Rothstein
The New York Times

October 23, 1999

Some 50 years ago, the science fiction writer Isaac Asimov formulated the three laws of robotics. The first is, "A robot may not injure a human being or, through inaction, allow a human being to come to harm."

For the moment, there is nothing to worry about from the robot now under consideration. It has a pair of caterpillar treads, bent yellow arms with multiple sockets, touch sensors and two rubber bands. It even follows the second law of robotics: it obeys orders without question -- after a program is fed into its central processor via infrared signals from a desktop computer.

And so far, even the third law seems to be holding up: "A robot must protect its own existence as long as such protection does not conflict with the first or second law." The two touch sensors turn off the power when the robot reaches the edge of the table, preventing destruction on the floor below.

But the future may be less certain as these robots evolve. Similar constructions, created out of Lego blocks and the Lego Mindstorms Robotics Invention System, are proliferating. The $219 set, which contains familiar Lego pieces along with light sensors, motors, touch sensors, gears and a minicomputer "brick," has been an immense success since its introduction last year. A Lego machine is made with the brick at its center. Then a program is written on a computer and beamed into an infrared sensor on the robot, which is then set free to follow its prescribed orders. Lego is now introducing a Star Wars Droid kit ($109), in which the robots take on forms resembling the films' quirkiest characters, and a Discovery robot set ($159) for more elementary constructions that don't require a computer to program.

What is most astonishing, though, is not one's ability to instruct that yellow-armed table-sensor robot to back up from the edge, nor to make an R2D2 model that will respond to coded signals from a flashlight. It is what happens once technologically sophisticated adults get hold of these machines' primitive abilities. Mindstorms robots have become techno-toys with as much appeal as the latest Nokia phone or Palm Pilot organizer. One Silicon Valley start-up company, Nuvo Media, had to make an office rule: no Lego play during work hours. One inventor, Anthony Fudd, has created an elementary motorized copy machine with the Mindstorms set that uses only one non-Lego part: the pen that is raised and lowered as it sketches out the copy.

Hackers have gone to work on the Lego computer brick, dissecting its hardware, and the Internet has become host to proliferating robotic improvisations. (There are discussions at, Lego's own, and such hacker sites as Now two books are being published with more sophisticated robotic instructions, engineering ideas and new programming languages: "Lego Mindstorms" by Jonathan B. Knudsen (O'Reilly & Associates) and the forthcoming "Definitive Guide to Lego Mindstorms" by Dave Baum (Apress).

The results might seem a far cry from the model towns that children began building out of interlinking Lego pieces in the 1950's. But there are deep connections between the old and the new, say, the minutely detailed pirate ship with monkeys hanging from the riggings that Lego produced in 1989 and Knudsen's invention of a Minerva Lego robot with a mechanical grasping arm. The transition not only illustrates the evolution of technological play but also reveals something about how computer technology itself might be understood and even taught.

The very name of the Lego robot set, Mindstorms, is taken from the 1980 book of the same name by Seymour Papert, a computer scientist at the Massachusetts Institute of Technology who argued that training in computer programming may be one of the most promising ways to teach children about the nature of problem solving. Lego later financed some of his research, and an early version of the Lego programmable brick was developed at the M.I.T. Media Lab.

What has been the nature of Lego's evolution? Consider the style of Lego that has been in place since the Danish company produced its first plastic pieces in 1949. The basic Lego element has always been the rectangular brick marked with circular studs; before the 1970's, it seems as if no curved elements were created at all. Even when curved shapes were created for use in particular models of ships or cars, the brick esthetic ruled: the point wasn't to hide the bricks but to show how their edges and protrusions could be used to suggest curves and movement. The more "pure" the Lego model, the less use it has of specialized pieces with unusual properties. Part of the appeal of a Lego model is that it displays its origins by showing its mechanical skeleton; that skeleton is all the more astonishing because it can be reorganized to form an entirely different body.

This is what makes Lego seem like a technological toy, even when the models are nontechnological. Many of the models of the 1980's, including towns and castles and pirates, are parts of traditional children's fantasies; almost all of them (aside from the various machinelike Technic toys) are also pretechnological in character. But the meaning of technology -- the word grows out of Greek linguistic roots invoking craft, making and mastery -- is evident not just in the process of their construction but also in the nature of their appearance. While some toys are put together to seem as if they weren't put together, Legos proclaim their own making; they display their technology. And the Lego instruction booklets are often exquisite demonstrations of the process behind the display. There are no words, only images. Pieces that previously seemed inconsequential turn out to serve an important purpose; there is continuing surprise as form and function align.

But this notion of Lego technology is not just metaphorical. What is being learned in classic Lego construction is a kind of digital language. The use of block accumulations to create illusions of smoothness is not unlike the way discrete numbers become waves of sound in the playing of a CD. In addition, a practiced Lego builder gradually learns that there are certain ways in which pieces are combined again and again to create arches, axles, walls, turrets, gear systems; they could almost be conceived of as modules, small models that are regularly called upon for continued use in larger systems.

This is very close to the way one has to think to make computer programs. There are very few "smooth" instructions, instructions that might tell a mechanical robot, for example, "Turn in a circle." Instead every smooth idea has to be broken down into the smallest individual steps: turning in a circle requires moving in minuscule movements up and across while slowly shifting direction, each moment of which must be specified in a program. Moreover, every programming language has certain procedures that are needed again and again; like the Lego modules, these miniprograms become ready-made ingredients for use in larger systems.

So Lego construction and computer programming already have certain similarities. And the Lego programming language for Mindstorm robots -- based on a language developed by Papert at M.I.T. -- makes those parallels clear. The program is constructed on the screen of the computer. Each instruction appears as a colored block that is then connected to another block. One block on the screen, might start the robot's power; the next might choose its direction of motion, and a third might instruct it to check a sensor and move only if a light is on. Lego also has an educational division, Dacta, that develops extensive curricula for schools and uses more advanced robotic programming languages developed at Tufts University.

Papert, who studied with Jean Piaget, has argued that this constructive process is also precisely the one by which children's education should take place. Computer literacy is not a matter of knowing how to use Microsoft Word; it is a matter of understanding how computers "think" and how humans might learn from thinking like a computer.

For example, Papert developed an early version of a robot he called a Turtle that moved on the floor, following explicit instructions from a computer. Children had to figure out precisely which instructions would cause the motion they desired. They had to dissect the motion and then reconstruct it. Papert has argued that all construction inspires learning, and all learning is a form of construction.

Papert's successor at M.I.T.'s Media Lab, Mitchel Resnick, is working on objects that may become the next generation of Lego Mindstorms, including small computer blocks called "crickets," which not only receive programs from a PC but also send instructions to each other.

"Our goal," he said in an interview, "is to bring back a craft spirit. We think of computers as a new kind of material used to create things in the world." The computer, he suggested, should seem more like modeling clay or finger paint and less like television.

This celebration of material manipulation gives the Lego robots an even closer connection to traditional Legos than many of the other Lego sets that have recently been made. Several years ago, as Lego was being overshadowed by video games and other forms of electronic play, Lego styles changed. The company developed sets aimed at girls (which were far less successful here than in Europe) while making other attempts to rival video games. Models were created that make sound and flash lights. Lego machines were used in duels, with scores being kept by electronic counters. Objects began to take on the fantastical appearance of the latest sci-fi fantasies.

Instead of castles, there are Insectoid space ships shaped like spiders and beetles. Instead of a medieval catapult, there is a Sting ray submarine with a swinging tail ostensibly searching for magic crystals. Technology runs wild. The ornate sets have many specialized parts -- green windshields, insect wings, rock grinders -- that could fit in no other application, something that almost violates the elegant principles of Lego building.

The new Star Wars models hark back a bit more to the technological spirit of traditional Legos, despite their specialized accouterments. They are at the same time stringent and fantastical.

But it is in the Mindstorms and Droid sets that the old Lego principles fully come into their own: the use of the blocks and the creation of the programs are interwoven activities. Lego has celebrated the act of making while displaying that act in the objects being made: the Mindstorms creations, with their mixture of engineering and programming, combine pretech mechanisms and high-tech software and celebrate the union of making and thinking. Who knows where this might lead? Voice synthesizers, subtle motor control, musical abilities, robots conversing -- perhaps, one day, we will even come to be grateful for Asimov's three laws.

Copyright 1999