Logo: How Logo Turtle Graphics Taught Children Programming

Logo is an educational programming language created in 1967 at Bolt, Beranek and Newman (BBN) in Cambridge, Massachusetts, by Wally Feurzeig, Seymour Papert and Cynthia Solomon. It is a dialect of Lisp with friendlier syntax, and it is best known for the turtle, a cursor or small robot that children steer with commands. Looking at how Logo turtle graphics taught children programming also shows how a whole philosophy of learning, not just a language, came out of 1960s computer science.

Origins at BBN and MIT

Seymour Papert was a mathematician who had spent several years in Geneva working with the developmental psychologist Jean Piaget. He believed children learn best by building things and testing their own ideas. At BBN, Feurzeig led a group exploring computers in education, and the three designers created Logo as a language children could use to explore mathematics and language, not as a cut-down version of an adult language.

The first versions ran on BBN's time-sharing systems and were tested with schoolchildren. Papert then founded the Logo Group at the MIT Artificial Intelligence Laboratory, where Logo work continued through the 1970s on PDP-10 and PDP-11 computers.

How Logo turtle graphics taught children programming

The turtle came a few years after the language itself. The first turtles were small robots that moved across the floor, connected to the computer by a cable, with a pen that could be raised or lowered to draw. Later, as graphics displays became available, the turtle moved onto the screen as a triangle.

The key idea was body syntonicity, Papert's term for connecting abstract ideas to a child's own body. A child who wants to draw a square can walk one: forward, turn right, forward, turn right. Then they write the same thing for the turtle:

• FORWARD 50 moves the turtle 50 steps in the direction it is facing.
• RIGHT 90 turns it 90 degrees without moving.
• PENUP and PENDOWN control whether it draws.
• REPEAT repeats a list of instructions.

Because the turtle thinks in its own position and heading, rather than x and y coordinates, children could reason about geometry from the inside. When a drawing came out wrong, they "debugged" it, and Papert argued that treating mistakes as bugs to fix, rather than failures, was one of the most valuable things Logo taught.

A short Logo example

TO SQUARE :SIZE
  REPEAT 4 [FORWARD :SIZE RIGHT 90]
END

TO FLOWER
  REPEAT 36 [SQUARE 60 RIGHT 10]
END

FLOWER

TO defines a new procedure, :SIZE is an input, and once defined, SQUARE works just like a built-in command. Drawing 36 squares, each turned 10 degrees, produces a rosette, a classic first "aha" moment for students.

Logo in schools and homes

Logo reached a wide audience in the early 1980s. Papert's 1980 book Mindstorms: Children, Computers, and Powerful Ideas made the case for children programming computers rather than computers programming children. Logo Computer Systems Inc. (LCSI), co-founded by Papert, and Terrapin both released Logo for the Apple II, and versions followed for the Commodore 64, the TI-99/4A, Atari machines and the IBM PC. Thousands of schools adopted it.

In the late 1980s, LEGO/Logo connected the language to motors and sensors built from LEGO bricks, an idea that led to the LEGO Mindstorms kits, named after Papert's book.

Influence and legacy

Logo's influence is wider than its own user base:

• Alan Kay visited Papert's group, and Logo's ideas about children and computing shaped the thinking behind Smalltalk at Xerox PARC.
• StarLogo and NetLogo extended the turtle to thousands of agents for modelling ecosystems, traffic and markets.
• Scratch, from the MIT Media Lab's Lifelong Kindergarten group led by Mitchel Resnick, a former student of Papert, carries Logo's philosophy into block-based programming.

Turtle graphics also became a standard teaching tool elsewhere; Python ships a turtle module in its standard library.

Is Logo still used today?

Logo itself is now a niche, but not a dead one. UCBLogo, written by Brian Harvey at Berkeley, and FMSLogo are free and still run on modern systems, and Harvey's Computer Science Logo Style books remain online. For most classrooms, Scratch and Python turtle have taken its place. Still, every one of those tools shows how Logo turtle graphics taught children programming: start with something you can see, let mistakes become bugs, and build bigger ideas from small procedures.

Frequently asked questions

Is Logo a real programming language or just for drawing?

Logo is a full programming language and a dialect of Lisp. It supports recursion, lists, words, variables and user-defined procedures. Turtle graphics is simply its best-known feature, and Logo has been used for text processing, music and AI examples too.

What age is Logo suitable for?

Logo was designed with children in mind, and early research worked with elementary and middle school students. Simple turtle commands work for young children, while recursion and list processing can challenge university students. Brian Harvey's books use Logo to teach serious computer science.

What is the difference between Logo and Scratch?

In Logo you type commands as text, while Scratch uses drag-and-drop blocks that cannot produce syntax errors. Scratch also adds sprites, sound and event-driven scripts. Both share the same idea that children should create things rather than just consume them.