The Logo Turtle

My first exposure to programming was as a nerdy elementary schooler playing with Logo, a simple computer language written for educational use as a way to teach basic concepts in programming and computer science. The language controls the behavior of the “turtle,” a triangular cursor in the middle of the screen that can be programmed to move around and draw lines.
i-40db705ca51619b38dc4c9f82d7ab956-logo-thumb-525x151-25499.pngIn one of the kid’s versions I remember that the cursor even looked like a little turtle on the screen, not just a triangle. As you probably could tell, I’m fascinated by how computer scientists use language from living things and biology in their programs, even something as simple as calling a cursor a “turtle”. What I didn’t know until I saw this article over at cyberneticzoo today is that the turtle was named after an actual robot that was used in the early 1970s as a physical “cursor” that was controlled by the program, moving around on a piece of paper and drawing lines with a marker. The robot was a little dome that looked kind of like a turtle shell, hence the name!

The Logo turtle itself was based on an even earlier robot, Grey Walter’s tortoise from the late 1940s. The tortoise was, like the turtle after it, a round, three-wheeled, slow-moving robot that was able to sense light and move towards its charging station when it ran out of batteries. Grey Walter’s research focused on trying to recreate the complexity of the animal brain with analog electronic processing, to see how simple wiring could lead to complex behavior. He was working explicitly on creating artificial life, even giving his robots pretend species names like Machina docilis or Machina spectulatrix, with simple “brains” that were able to learn from their experiences and even have a degree of “self-awareness”, watching themselves in the mirror, “Twittering, and jigging like a clumsy Narcissus.”

It’s amazing how such simple robots can seem so alive, so actually “turtle-like.” These friendly, animal-like robots are so interesting in the way that we design them to mimic living creatures and in the way that we relate to them and use them for all sorts of different things. It’s no surprise that the Roomba looks and behaves a lot like the Logo turtle.


  1. #1 Nathan Zeldes
    January 13, 2010

    Logo was a very nice language indeed… to us grown-ups. It was supposed (by grown-ups) to be just right for teaching kids to code, but when I got it back in the 80s and taught my kids how to use it (on a C-64) they made a few spirals and very soon dropped it in favor of BASIC (yuck!). Maybe they were too young to be impressed by the logic and elegance of the language the way I was :-)

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