Week 1 - Intro to the course and Turtle Geometry

Date: 2024-01-28

Turtle

Today

Trailer

multiple neighborhood cellular automata, by softology

Intro

This class will be taught like a lab.

Each week we will do at least one experiment or workshop where we explore new ideas in art and code. I will introduce at least one new concept or technique, then students will work in small groups or solo in a “jam” style, spending time experimenting and building projects that expand on the concept.

STUDENTS ARE EXPECTED TO DOCUMENT THEIR WORK EACH WEEK OF THE SEMESTER THROUGH A DEVELOPMENT LOG (DEVLOG). This is also one of the primary ways we will evaluate student work and progress throughout the semester.

Hello!

What will be learning?

Syllabus

We have one!

Turtle Lesson 1

Turtles Standard Route

Bits and Bytes was the name of two Canadian educational television series that taught the basics of how to use a personal computer. It was aired in 1983.

LOGO commands with visual output
example LOGO commands with visual result (image from Logo Foundation)

Logo is an educational programming language, designed in 1967 by Wally Feurzeig, Seymour Papert, and Cynthia Solomon. 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 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.

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-controlled 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.

Turtle robot

Turtle robot with eyes
LOGO Robot “with eyes” at MIT, 1974, via Harvey Cohen

Logo’s most-known feature is the turtle (derived originally from a robot of the same name),[5] 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.

Logo example on screen
A more complex LOGO program with loops (repeat), via Wikipedia

Apple LOGO II

Example commands

FORWARD 100

FORWARD RANDOM 100

LEFT 90

REPEAT 10 [LEFT 30 FD 30]

Apple LOGO commands

A short list of commands. There are more you can look up in the bookmarked notes below.

CLEARSCREEN - Clear the screen. (Shorthand: CS)
HIDETURTLE - Don't show the turtle cursor. (HT)
SHOWTURTLE - Show the turtle cursor. (ST)
HOME - Move back to the home position.
FORWARD steps - Move forward steps. (FD)
BACK steps - Move back steps. (BK)
LEFT degrees - Turn left this many degrees. Negative degrees work too, they'll turn it right. (LT)
RIGHT degrees - Turn right this many degrees. (RT)
SETHEADING degrees - Turn to an absolute heading of degrees. (SETH)
SETPOS [x y] - Set the position to x, y coordinates. These are Cartesian, so 0,0 is the middle of the screen.
SETX x - Set the horizontal position to x.
SETY y - Set the vertical position to y.
RANDOM n  //returns an integer between 0 and n
PRINT x   //prints out contents of x on console

LOGO for Apple II resources

Draw an image. Screenshot it and submit.

Working in groups or solo, transition to working with JSLogo, an implementation of the LOGO language written in Javascript for the Web.

Link to JSLogo Interpreter

JSLogo includes an online reference, library of your procedures (functions), history, example code, extras, links to documentation, and even collaboration features.

To figure out

Making a Quilt Patch

In order to create a communal quilt, we need to agree upon dimensions. Let’s use the following procedure, frame, as the base for all of our patches. It creates a black 100 X 100 square.

to frame
pd
repeat 4 [fd 100 rt 90]
end

Rules: The only rule is that your turtle must return to its original position and heading at the end of the design.

idea source: Gary Stager Old Fashioned Logo Quilt-Making

Resources

Homework

Reading

Project 1: A Logo Crazy Quilt

For this project your job is to define digital ‘quilt blocks’ that can be drawn in LOGO, then have your Turtle create a random block crazy quilt constructed out of these pieces.

Steps: * Create a standard quilt ‘block’ recipe. The turtle should start at the top left, draw a block, then finish at the top right corner (so that it can begin drawing the next). * Then make more quilt blocks of many variations. * Write a program that starts the turtle at the top left, picks a random block to draw, then another, then another…Every 6 blocks the turtle should move to the left side of the quilt and one row down. The turtle should draw 8 rows of 6 blocks.

Note: You are allowed (and encouraged) to work collaboratively on this project.

Method:

Assume a standard square block size of 40 by 40 pixels. Note: we may alter this size in class if we deem it too small.

Create a function to move your turtle to the top left.

Create a function to draw a quilt block.

Create more quilt blocks as functions.

Create a function that is a random chooser that will pick a quilt block function at random to draw.

Create a row function that draws 6 random blocks then moves to the left side and down one block.

Put it all together.

Development Logs (Devlogs)

A devlog is a way to capture our work in progress.

In this course we will be constantly experimenting. Our work may break. We may do dozens, perhaps hundreds, of iterations while we work. We may produce finished projects and these may serve as in-progress updates, or our projects may not come to fruition and instead live-out in posts with a screenshot or two or a research image and a few lines description and some code snippets.

Dev stands for development and refers to how we slowly over time work to develop our projects iteratively.

Why keep a devlog (beyond because I’m asking you to for our class)?

Writing about your projects helps you formulate ideas, struggle to find solutions, and let you reflect on choices you may have made intuitively. A devlog serves as a digital notebook that you can refer back to later (months, years?) when you need to re-learn how to do something you’ve forgotten. It’s also a way to organize your thoughts. It can turn into sources you refer to when building a portfolio. Or just serve as an internal way to see your own progress in learning and making. It can also be a way to share your own knowledge or art with others. And it may even lead to people getting in touch to talk about your ideas or art. It’s also a good practice to keep a devlog when working on longterm projects like one’s senior project.

Example logs

These are example devlogs by artists, designers and programmers writing about their projects and especially their research and mid-stage projects:

Writing

Start with a step by step description of what you worked on in order, including images potentially.

Next, describe particular areas of investigation, things you figured out, things you got stuck on. You can also describe areas that appear promising or most compelling, and what questions you still might have or areas to explore further.

What are your thoughts on LOGO itself? Do you find the ideas behind the language compelling? How does it relate to things you already know (or not?)

Bonus

Atari Cambridge Research - LOGO programs to produce dances and dancing marionettes and maze programs navigable via Joystick.

Turtle icon by Freepik