2. What Is “LOGO”? LOGO is a computer programming language used for functional programming. Today it is known primarily for its "turtle" graphics, but can also be used for handling lists, files, and I/O. Turtle graphics is a term in computer graphics for a method of programming vector graphics using a relative cursor (the "turtle") upon a Cartesian plane. The turtle moves with commands that are relative to its position, such as "move forward 100 spaces" and "turn left 180 degrees". Enabling it, setting its color, or setting its width can also control the pen carried by the turtle. A programmer can (as I have) understand, predict, reason about the turtle's motion by imagining what they would do if they were the turtle. Seymour Papert, the inventor of LOGO programming language, called this "body syntonic" reasoning.
3. Why Make A LOGO Program? When using the body syntonic reasoning method, you would have to guess the angle, how far to move forward, then if you mess up you might have to undo a very difficult step to get another shot at drawing the shape. Generally, it takes a lot of practice for body syntonic reasoning to become practical. I asked myself “Isn’t there a faster and simpler way to draw a perfect square, triangle, or any other shape?” After doing some research on how to create a LOGO program, I decided that I would create a program making shape drawing easier and less time consuming. By successfully creating a program where you simply type the shape and size, the average user can build a shape in less than three seconds.
4. Hypothesis My hypothesis was that this program would not only produce shapes, but also produce them in less time than using the body syntonic method. First, I calculated the time it took to draw certain shapes. To draw a square it took me ten seconds, to draw a triangle it took 10 seconds, and to draw a hexagon it took me 20 seconds. After recording the times to draw each shape, I began constructing my program.
5. Introduction When you first open up MSWLogo, the program I used to create my LOGO program, it looks very simple. It’s a triangular-shaped cursor, or the “turtle”, sitting in the middle of a vast white screen. You also see a command bar. Despite the unsophisticated appearance, LOGO is capable of doing complex actions like animations, problem solving, and even create games. You can program certain buttons to do special actions and even play music. First, though, you have to know the LOGO language for the program you want to create.
6. Introduction LOGO already comes with some programmed commands. “FD 100” would move the turtle forward 100 spaces; “LT 90” will point the turtle to the left at a ninety-degree angle, and “RT 45” will point the turtle to the right at a forty-five-degree angle. Other commands include “CS” which is to clear the drawing space, typing, “EDIT” then typing a word (EDIT “crazy) which is for you to program what the command “crazy” will do, and many others. LOGO relies on you to use "body syntonic" reasoning. Body syntonic reasoning is defined by Seymour Papert, the inventor of LOGO programming language, as understanding, predicting, and reasoning about the turtle's motion by imagining what they would do if they were the turtle. Although I think it is an excellent concept, in reality when using LOGO it can become time consuming. You are literally relying on guesses and hunches to draw shapes. After getting fed up with the long and drawn-out body syntonic method, I decided to create a program for LOGO that makes shape drawing easier.
8. Step ONE I began by listing all of the shapes I wanted in my program and how many sides they had. To program LOGO to automatically draw any shape, it must know how many sides the shape has.
9. Step TWO After recording the sides of the shapes, I then started to program the shapes into LOGO. To program LOGO to draw a square on command, I have to tell LOGO that a square has four sides and four ninety-degree angles. I also have to tell LOGO that I will choose the size. You could also tell LOGO what color you want it to be, but I opted not to do that.
10. Step THREE For the triangle, I told LOGO that it has three sides and three forty-five-degree angles. I then told LOGO that I will choose the size. I continued this cycle for the rest of the shapes, program the side and angles while keeping the size up to the user to choose. I made sure the commands to draw the shapes were simple. For example, typing the command “square” and the size such as “100” will give you a square one-hundred turtle steps big.
11. Even EASIER!! To make it even easier, I programmed a “polygon” feature. I programmed LOGO to draw any shape when given the “polygon” command, the sides, and the size of the shape you want. To do this, I told LOGO that the command “polygon” would allow the user to choose the side and the size of the shape. For example, the command “polygon 8 100” will give you an eight-sided sided shape one hundred turtle steps big.
13. SUCCESS! When I ran the finished program, I had successfully made the process of drawing shapes seem effortless. What had previously taken me an average of twelve seconds now takes an average of one second, reducing the time by eleven seconds. After testing the program, I saved it and burned it onto a CD.
14. References/APA Bibliography Author, Mike Koss ,(1996) Learning LOGO. Retrieved from http://mckoss.com/logo/ Author, Roy D. Pea, (1987) Logo programming and problem solving. Technical Report. Retrieved from http://scholar.google.com/scholar?q=LOGO+programming&hl=en&as_sdt=40000000001&as_sdtp=on
