The turtle moves with commands that are relative to its own position, LEFT 90 means spin left by 90 degrees. 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.Īs a practical matter, the use of turtle geometry instead of a more traditional model mimics the actual movement logic of the turtle robot. It has traditionally been displayed either as a triangle or a turtle icon (though it can be represented by any icon). 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.

The virtual and physical turtles were first used by fifth-graders at the Bridge School in the same city in 1970–71.Īnimated gif with turtle in MSWLogo ( Cardioid) The earliest year-long school users of Logo were in 1968–69 at Muzzey Jr. At BBN Paul Wexelblat developed a turtle named Irving that had touch sensors and could move forwards, backwards, rotate, and ding its bell. The first turtle was a tethered floor roamer, not radio-controlled or wireless. Modern Logo has not changed very much from the basic concepts predating the first turtle. A display turtle preceded the physical floor turtle. The first working Logo turtle robot was created in 1969. The use of virtual Turtles allowed for immediate visual feedback and debugging of graphic programming. Modeled on LISP, the design goals of Logo included accessible power and informative error messages. The goal was to create a mathematical land where children could play with words and sentences. The first implementation of Logo, called Ghost, was written in LISP on a PDP-1. The first four years of Logo research, development and teaching work was done at BBN.

Its intellectual roots are in artificial intelligence, mathematical logic and developmental psychology. Logo was created in 1967 at Bolt, Beranek and Newman (BBN), a Cambridge, Massachusetts research firm, by Wally Feurzeig, Cynthia Solomon, and Seymour Papert. Logo is not case-sensitive but retains the case used for formatting purposes. Logo is usually an interpreted language, although compiled Logo dialects (such as Lhogho and Liogo) have been developed.

There is no standard Logo, but UCBLogo 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 did in his Computer Science Logo Style trilogy. Logo is a multi-paradigm adaptation and dialect of Lisp, a functional programming language. 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. The language was conceived to teach concepts of programming related to Lisp 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. 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.Ī 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. Logo is an educational programming language, designed in 1967 by Wally Feurzeig, Seymour Papert, and Cynthia Solomon.

Symmetry around a point can be obtained using only a few instructions, allowing users to draw hypotrochoids like the one shown here.

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