Logo is an educational programming language, designed in 1967 by

Wally Feurzeig Wallace "Wally" Feurzeig (June 10, 1927 – January 4, 2013) was an American computer scientist who was co-inventor, with Seymour Papert and Cynthia Solomon, of the programming language Logo, and a well-known researcher in artificial intellige ...

, Seymour Papert, and

Cynthia Solomon Cynthia Solomon is an American computer scientist known for her work in artificial intelligence (AI) and popularizing computer science for students. She is a pioneer in the fields of artificial intelligence, computer science, and educational co ...

. ''Logo'' is not an acronym: the name was coined by Feurzeig while he was at Bolt, Beranek and Newman, and derives from the Greek ''logos'', meaning ''word'' or ''thought''. A general-purpose language, Logo is widely known for its use of turtle graphics, in which commands for movement and drawing produced line or vector graphics, either on screen or with a small robot termed a turtle. The language was conceived to teach concepts of programming related to

Lisp A lisp is a speech impairment in which a person misarticulates sibilants (, , , , , , , ). These misarticulations often result in unclear speech. Types * A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lisping ...

and only later to enable what Papert called " body-syntonic reasoning", where students could understand, predict, and reason about the turtle's motion by imagining what they would do if they were the turtle. There are substantial differences among the many dialects of Logo, and the situation is confused by the regular appearance of turtle graphics programs that are named Logo. Logo is a

multi-paradigm Programming paradigms are a way to classify programming languages based on their features. Languages can be classified into multiple paradigms. Some paradigms are concerned mainly with implications for the execution model of the language, suc ...

adaptation and dialect of Lisp, a functional programming language.CSLS Vol 1, Preface .pxvi, Harvey 1997 There is no standard Logo, but

UCBLogo UCBLogo, also termed Berkeley Logo, is a programming language, a dialect of Logo (programming language), Logo, which derived from Lisp (programming language), Lisp. It is a dialect of Logo intended to being a “minimum Logo standard.” It has ...

has the best facilities for handling lists, files, I/O, and recursion in scripts, and can be used to teach all computer science concepts, as UC Berkeley lecturer

Brian Harvey Brian Lee Harvey (born 8 August 1974) is a British singer from London. He was the lead singer of pop group East 17. The later incarnation of the band, E-17, had two top 20 singles on the UK Singles Chart between 1998 and 1999, with the album ' ...

did in his ''Computer Science Logo Style'' trilogy.''Computer Science Logo Style'', Brian Harvey, MIT Press (3 volumes) , , . Availabl
online
Logo is usually an interpreted language, although compiled Logo dialects (such as Lhogho and Liogo) have been developed. Logo is not case-sensitive but retains the case used for formatting purposes.

History

Logo was created in 1967 at Bolt, Beranek and Newman (BBN), a Cambridge, Massachusetts research firm, by

, and Seymour Papert. Its intellectual roots are in artificial intelligence, mathematical logic and

developmental psychology Developmental psychology is the science, scientific study of how and why humans grow, change, and adapt across the course of their lives. Originally concerned with infants and children, the field has expanded to include adolescence, adult deve ...

. The first four years of Logo research, development and teaching work was done at BBN. The first implementation of Logo, called Ghost, was written in

LISP A lisp is a speech impairment in which a person misarticulates sibilants (, , , , , , , ). These misarticulations often result in unclear speech. Types * A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lisping ...

on a PDP-1. The goal was to create a mathematical land where children could play with words and sentences. Modeled on LISP, the design goals of Logo included accessible power and informative error messages. The use of virtual Turtles allowed for immediate visual feedback and debugging of graphic programming. The first working Logo turtle robot was created in 1969. A display turtle preceded the physical floor turtle. Modern Logo has not changed very much from the basic concepts predating the first turtle. The first turtle was a tethered floor roamer, not

radio-control Radio control (often abbreviated to RC) is the use of control signals transmitted by radio to remotely control a device. Examples of simple radio control systems are garage door openers and keyless entry systems for vehicles, in which a smal ...

led or wireless. At BBN Paul Wexelblat developed a turtle named Irving that had touch sensors and could move forwards, backwards, rotate, and ding its bell. The earliest year-long school users of Logo were in 1968–69 at Muzzey Jr. High in Lexington, Massachusetts. The virtual and physical turtles were first used by fifth-graders at the Bridge School in the same city in 1970–71.

Turtle and graphics

Logo's most-known feature is the turtle (derived originally from a robot of the same name), an on-screen " cursor" that showed output from commands for movement and small retractable pen, together producing line graphics. It has traditionally been displayed either as a triangle or a turtle icon (though it can be represented by any icon). Turtle graphics were added to the Logo language by Seymour Papert in the late 1960s to support Papert's version of the turtle robot, a simple robot controlled from the user's workstation that is designed to carry out the drawing functions assigned to it using a small retractable pen set into or attached to the robot's body. As a practical matter, the use of turtle geometry instead of a more traditional model mimics the actual movement logic of the turtle robot. The turtle moves with commands that are relative to its own position, ''LEFT 90'' means spin left by 90 degrees. Some Logo implementations, particularly those that allow the use of concurrency and multiple turtles, support collision detection and allow the user to redefine the appearance of the turtle cursor, essentially allowing the Logo turtles to function as sprites. Turtle geometry is also sometimes used in environments other than Logo as an alternative to a strictly coordinate-addressed graphics system. For instance, the idea of turtle graphics is also useful in Lindenmayer system for generating

fractal In mathematics, a fractal is a geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scales, as illu ...

Implementations

Some modern derivatives of Logo allow thousands of independently moving turtles. There are two popular implementations: Massachusetts Institute of Technology's StarLogo and Northwestern University Center for Connected Learning's (CCL) NetLogo. They allow exploring

emergent phenomena In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole. Emergence ...

and come with many experiments in social studies, biology, physics, and other areas. NetLogo is widely used in agent-based simulation in the biological and social sciences. Although there is no agreed-upon standard, there is a broad consensus on core aspects of the language. In March 2020, there were counted 308 implementations and dialects of Logo, each with its own strengths. Most of those 308 are no longer in wide use, but many are still under development. Commercial implementations widely used in schools include ''

MicroWorlds MicroWorlds is a program that uses the Logo programming language to teach language, mathematics, programming, and robotics concepts in primary and secondary education. It features an object in the shape of a turtle that can be given commands to mo ...

Logo'' and ''Imagine Logo''. Legacy and current implementations include:

First released in 1980s

* Apple Logo for the Apple II Plus and Apple Logo Writer for the Apple IIe, developed by Logo Computer Systems, Inc. (LCSI), were the most broadly used and prevalent early implementations of Logo that peaked in the early to mid-1980s. * Aquarius LOGO was released in 1982 on cartridge by Mattel for the

Aquarius Aquarius may refer to: Astrology * Aquarius (astrology), an astrological sign * Age of Aquarius, a time period in the cycle of astrological ages Astronomy * Aquarius (constellation) * Aquarius in Chinese astronomy Arts and entertainment ...

home computer. * Atari Logo was released on cartridge by Atari for the

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. * Color Logo was released in 1983 on cartridge (26-2722) and disk (26-2721) by Tandy for the TRS-80 Color Computer. * Commodore Logo was released, with the subtitle "A Language for Learning", by Commodore Electronics. It was based on MIT Logo and enhanced by Terrapin, Inc. The

Commodore 64 The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...

version (C64105) was released on diskette in 1983; the

Plus/4 The Commodore Plus/4 is a home computer released by Commodore International in 1984. The "Plus/4" name refers to the four-application ROM resident office suite (word processor, spreadsheet, database, and graphing); it was billed as "the produc ...

version (T263001) was released on cartridge in 1984. * ExperLogo was released in 1985 on floppy by Expertelligence Inc. for the

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. * Hot-Logo was released in the mid-1980s by EPCOM for the

MSX MSX is a standardized home computer architecture, announced by Microsoft and ASCII Corporation on June 16, 1983. It was initially conceived by Microsoft as a product for the Eastern sector, and jointly marketed by Kazuhiko Nishi, then vice-p ...

8-bit computers with its own set of commands in Brazilian Portuguese. * TI Logo (for the

TI 99/4A The TI-99/4 and TI-99/4A are home computers released by Texas Instruments in 1979 and 1981, respectively. Based on the Texas Instruments TMS9900 microprocessor originally used in minicomputers, the TI-99/4 was the first 16-bit home computer. ...

computer) was used in primary schools, emphasizing Logo's usefulness in teaching computing fundamentals to novice programmers. * Sprite Logo, also developed by Logo Computer Systems Inc., had ten turtles that could run as independent processes. It ran on Apple II computers, with the aid of a Sprite Card inserted in one of the computer's slots. * IBM marketed their own version of Logo (P/N 6024076), developed jointly by Logo Computer Systems, Inc. (LCSI), for their then-new IBM PC. * ObjectLOGO is a variant of Logo with object-oriented programming extensions and lexical scoping. Version 2.7 was sold by Digitool, Inc. It is no longer being developed or supported, and does not run on versions of the Mac operating system later than version 7.5. * Dr. Logo was developed by Digital Research and distributed in computers including the

IBM PCjr The IBM PCjr (pronounced "PC junior") was a home computer produced and marketed by IBM from March 1984 to May 1985, intended as a lower-cost variant of the IBM PC with hardware capabilities better suited for video games, in order to compete mor ...

, Atari ST and the Amstrad CPC. *

Acornsoft Logo Logo is an educational programming language, designed in 1967 by Wally Feurzeig, Seymour Papert, and Cynthia Solomon. ''Logo'' is not an acronym: the name was coined by Feurzeig while he was at Bolt, Beranek and Newman, and derives from the Gre ...

was released in 1985. It is a commercial implementation of Logo for the 8-bit BBC Micro and Acorn Electron computers. It was developed for Acorn Computers as a full implementation of Logo. It features multiple screen turtles and four-channel sound. It was provided on two 16kB

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * R ...

s, with utilities and drivers as accompanying software.

First released in 1990s

* In February 1990, ''Electron User'' published Timothy Grantham's simple implementation of Logo for the Acorn Electron under the article "Talking Turtle". * Comenius Logo is an implementation of Logo developed by Comenius University Faculty of Mathematics and Physics. It started development in December 1991, and is also known in other countries as SuperLogo, MultiLogo and MegaLogo. *Lego Logo is a version of Logo that can manipulate robotic

Lego Lego ( , ; stylized as LEGO) is a line of plastic construction toys that are manufactured by The Lego Group, a privately held company based in Billund, Denmark. The company's flagship product, Lego, consists of variously colored interlocking ...

bricks attached to a computer. It was implemented on the

Apple II The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-m ...

computing platform and was used in American and other grade schools in the late 1980s and early 1990s. Lego Logo is a precursor to Scratch. *

, also known as Berkeley Logo, is a free, cross-platform implementation of standard Logo last released in 2009. George Mills at MIT used UCBLogo as the basis for

MSWLogo MSWLogo is a programming language which is interpreted, based on the computer language Logo, with a graphical user interface (GUI) front end. It was developed by George Mills at the Massachusetts Institute of Technology (MIT). Its core is the sam ...

which is more refined and also free. Jim Muller wrote a book, ''The Great Logo Adventure'', which was a complete Logo manual and which used MSWLogo as the demonstration language. MSWLogo has evolved into

FMSLogo ''FMSLogo'' is a free implementation of a computing environment called Logo, which is an educational interpreter language. GUI and Extensions were developed by George Mills at MIT. Its core is the same as UCBLogo by Brian Harvey. It is free softw ...

First released from 2000 onwards

* aUCBLogo a rewrite and enhancement of

. * Imagine Logo is a successor of Comenius Logo, implemented in 2000. The English version was released by Logotron Ltd. in 2001. * LibreLogo is an extension to some versions of LibreOffice. Released in 2012, it is written in Python. It allows vector graphics to be written in Writer. * Logo3D is a tridimensional version of Logo. * POOL is a dialect of Logo with object-oriented extensions, implemented in 2014. POOL programs are compiled and run in the graphical IDE on

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

. A simplified, cross-platform environment is available for systems supporting

.NET Framework The .NET Framework (pronounced as "''dot net"'') is a proprietary software framework developed by Microsoft that runs primarily on Microsoft Windows. It was the predominant implementation of the Common Language Infrastructure (CLI) until bein ...

. * QLogo is an open-source and cross-platform rewrite of

with nearly full UCB compatibility that uses hardware-accelerated graphics. * Lynx is an online version of Logo developed by Logo Computer Systems Inc. It can run a large number of turtles, supports animation, parallel processes, colour and collision detection. * LogoMor is an open-source online 3D Logo interpreter based on JavaScript and p5.js. It supports 3D drawings, animations, multimedia, 3D models and various tools. It also includes a fully-featured code editor based on

CodeMirror CodeMirror is a JavaScript component that provides a code editor in the browser. It has a rich programming API and a focus on extensibility. History The first version of the editor was written early 2007, for the console in the Eloquent Java ...

* LbyM is an open-source online Logo interpreter based on JavaScript, created and actively developed (as of 2021) for Sonoma State University's ''Learning by Making'' program. It features traditional Logo programming, connectivity with a customized microcontroller and integration with a modern code editor.

Influence

Logo was a primary influence on the

Smalltalk Smalltalk is an object-oriented, dynamically typed reflective programming language. It was designed and created in part for educational use, specifically for constructionist learning, at the Learning Research Group (LRG) of Xerox PARC by Alan Ka ...

programming language. It is also the main influence on the Etoys educational programming environment and language, which is essentially a Logo variant written in Squeak (itself a variant of Smalltalk). Logo influenced the procedure/method model in

AgentSheets AgentSheets was one of the first modern block-based programming language for kids. The idea of AgentSheets was to overcome syntactic challenges found in common text-based programming languages by using drag and drop mechanisms conceptualizing com ...

and

AgentCubes AgentCubes is an educational programming language for children to create 3D and 2D online games and simulations. The main application of AgentCubes is as computational thinking tool teaching children computational thinking through game and simul ...

to program agents similar to the notion of a turtle in Logo. Logo provided the underlying language for Boxer. Boxer was developed at University of California, Berkeley and MIT and is based on a ''literacy model'', making it easier to use for nontechnical people. KTurtle is a variation of Logo implemented at Qt for the

KDE KDE is an international Free software movement, free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-know ...

environment loosely based on Logo. Two more results of Logo's influence are Kojo, a variant of Scala, and Scratch, a visual, drag-and-drop language which runs in a web browser.