Logo (programming language)

Logo (programming language)

Logo is a Lisp wearing child-friendly clothes — designed in 1967 at BBN by Wally Feurzeig, Seymour Papert, and Cynthia Solomon, named by Feurzeig from the Greek logos ("word" or "thought"). It was built on a heretical idea: children shouldn't just use computers, they should program them — and so it wrapped Lisp's power (lists, recursion, functional evaluation) in commands a five-year-old could say out loud. The first implementation — called Ghost — was written in LISP on a PDP-1.^[1]

The feature that made Logo immortal is the turtle — originally added by Papert in the late 1960s as a physical floor robot (Paul Wexelblat's "Irving," a tethered roamer with touch sensors and a bell) and an on-screen cursor that preceded it. Type FORWARD 10, RIGHT 90 and the turtle moves and draws — and the child, Papert argued, does something profound: they think body-syntonically, reasoning about the turtle by imagining being the turtle. The first schoolkids used Logo in 1968–69 at Muzzey Jr. High in Lexington, Massachusetts.^[2]

Mindstorms — children should program computers

Logo was always more than a language — it was the vehicle for Papert's theory of constructionism: that children learn best by building things they care about. His 1980 book Mindstorms laid it out — children should program computers, not the reverse — and Logo was the proof. The lineage runs straight through the decades: Logo → Apple's school machines → Etoys and NetLogo → Scratch, the block language millions of kids learn today, which is Logo's turtle in modern drag.^[3]

Where it sits

Logo is the gentlest proof that language is pedagogy: between JOSS (which made computing conversational for adults) and everything since, Logo asked whether a child could be the user — and built the whole educational-software industry on the answer. It's also the hidden thread linking BBN's PDP-1s to MUMPS (born there) and to every kid who's ever made a triangle crawl across a screen.

Check your understanding

• Who designed Logo, where, and what does the name mean?
• What was Ghost — and what machine did it run on?
• What was the original turtle — and which came first, screen or robot?
• What modern language is Logo's most direct descendant?