The History of Marvin Minski’s Logo

I recently attended a workshop hosted by the Logo Foundation, https://el.media.mit.edu/logo-foundation/, featuring the topic of "Minsky Logo". This workshop paid homage to Marvin Minsky.  Marvin Minsky, along with Seymour Papert, and Cynthia Solomon worked together to develop and implement Logo in a classroom environment.

Logo is a graphical programming language where children can instruct a "turtle" to move using a series of simple computer commands. The “turtle” can be either a virtual triangle on the computer screen or a physical device/robot moving across a floor.  The movement of the “turtle” follows a path which is analogous to a place in the computer’s memory. When the “turtle” is moved, a trail is recorded.  These trails can draw complex shapes and patterns as shown below.

A Minsky Logo Program

Marvin Minsky was one of the founding fathers of artificial intelligence at MIT and his goal was to make computers "think".  Seymour Papert, was a student of Jean Piaget in Switzerland where he developed theories of learning and the importance of hands-on discovery and exploration. He believed that technology could provide new ways for children to think. In 1963, Marvin Minsky invited Seymour Papert to join him at MIT to do research in intelligence. 

 Both Seymour and Marvin believed there was an interconnection of how children think and how to make machines think.  They both wrote papers about how to learn, one with children and the other with computers. In conclusion, they realized that their outcomes were exactly the same results.

Logo was created in the late 1960's at the Artificial Intelligence Lab at MIT for children to develop critical thinking and problem solving skills. In doing so, it established computers as a tool for learning. 

In 1973, Marvin Minsky built a physical device which he called a "turtle".  He named this device/robot a TT2500. TT is supposed to stand for Turtle Terminal and 2500 was their guess as to how much it would cost in retail dollars. It did not have enough memory to run the Logo program because it only had 4K of memory. The 4K memory was sufficient for the TT2500 to be run as a terminal by another computer in the PDP 11 family. The 4K chip was eventually replaced with a 64K chip four years later.  Interestingly enough, the new upgraded memory was sufficient to run Logo at the same price as its original memory as the cost of chips decreased significantly over time. While Marvin built the physical machine, his daughter, Margaret designed the circuitry for the text display.

After the construction of the TT2500, it was placed in a 7th grade classroom taught by a mathematics teacher for observation and implementation of learning Logo. It was here that Cynthia Solomon noticed that it was being implemented incorrectly.  The students were being taught with rout learning and were not given the time to explore the immense possibilities of Logo. Cynthia took over the class and her influence created an environment were Logo flourished.  Today Cynthia is known as the "mother of Logo" because she was the first to nurture and enable students to use Logo successfully. https://www.youtube.com/watch?v=maDzjHIiXZc

In Cynthia's classroom, the TT2500 could move on the floor with the Logo commands that were programmed into the machine. It was placed on butcher paper and lines were drawn with the movement of the turtle.  The turtle became a drawing instrument with the addition of a pen. 

Today, this early version of Logo can be emulated online because Brian Silverman produced the computer code to execute the Logo commands. https://www.playfulinvention.com/demos/MinskyLogo/  Brian Silverman was involved in Logo almost since the beginning of its development.

The Logo screen is divided into three sections. The bottom left area is where simple commands can be entered next to a flashing line. The top left area is where routines can be entered.  The turtle is a triangle in the center of the screen.  It is outlined in white on a black background. The turtle's playground is in this section.

Logo commands 

 fd - forward

 bk - back

 lt - left

 rt - right

 pu - pen up

 pd - pen down

 st - show the turtle

 ht - hide the turtle

 seth.(set heading) - rotate the turtle in a clockwise direction by a specified angle        from its home position.

 clean - Clears the screen of trails but the turtle remains where it is without moving

 repeat - repeat 3 [fd 60 rt 120] The square brackets indicate that the enclosed commands are to be executed three times.

During the workshop, Brian Silverman showed a 50 year old demo that displayed the capabilities of Logo. This program and others can be found in the examples at the bottom of this document.  https://playfulinvention.com/demos/MinskyLogo/help.txt

The TT2500 had a new command called spin because kids love animation. New computer hardware had to be built to accommodate this.  This was the era were hardware development needed to be done if you were serious about software development.

The above image is repeated twice and spun together.

The image spins through the set of all spirals which is appealing for children. Environments like this is Seymour Papert's vision of Mathland whereby children could explore mathematical ideas and concepts in a creative way instead of rout memorization and repetition.

Cynthia Solomon's favorite demo of Logo was this Ferris wheel.  The squares with the triangular tops(seats) rotate around a central point while the base remains static.

In conclusion, I really enjoyed this workshop. I loved exploring and recreating programs with Minsky's Logo.   It was interesting to hear about the origin of Logo and how it was applied in Marvin Miniski's Artificial Intelligence Lab at MIT. Logo became a tool to enhance learning and provided children with new ways to think.