CS 1150 PEEE   Logo: Turtle Graphics

Overview

We used Scratch to do turtle-graphics (Scratch II, Scratch III, and Scratch IV. The drawing tools we used there originated in the Logo programming language and are still part of the variants of Logo in use today, including NetLogo that we will be using. Your task here is to recreate one of your Scratch programs in NetLogo. You may work in pairs on this assignment if you wish—I encourage it. If you work in partnership, work together on the TARR, submitting only one copy. (Individuals in a partnership may submit a message indicating a partner, self or other, did not share fully in the work.)

NetLogo Information

You should already have seen the NetLogo environment and read the overview of the system (Nicholas Bennett's Core Concepts of NetLogo, a PDF). Some additional information is provided below.

• Additional help

  See the NetLogo documentation (http://ccl.northwestern.edu/netlogo/docs/) for additional information. I tend to focus my use on the NetLogo Dictionary and the Programming Guide in the links on the left side of the page.

• Remember many instructions are "turtle" commands and, thus, can not be used in the setup procedure except as part of the turtle creation instructions (or an ask turtles block).
• Patches have color (pcolor) and turtles have color (color). The pen uses the same color as the turtle, i.e., to set the pen color, set the turtles's color.
• Most instructions require operands (the instruction is an operator and needs things to operate on, the operands). See the code below for examples.
• You may want to change the "settings" for the world (click the "Settings..." button in the "Interface". I used 50 as the maximum x and y coordinates and set the patch size to 5.
• You can choose a non-standard (something beside the little triangle) for you turtle shape(s) if you want. While in the Code part of the system, click on the Tools menu and select "Turtle Shapes Editor" to see what is available. You might want to import something else form the library.

Some of the code I used is shown below. It should help you get started.

	to setup
	  clear-all
	  create-turtles 1
	  [
	    set color 45
	    set heading 0
	    set shape "face happy"
	    set pen-size 5
	  ]
	end

	to go
	  drawJ -30 15 30
	  drawP  -0 15 30
	  drawE  30 15 30
	end

	to drawJ [x y height]
	  ;  instructions for positioning the turtle
	  ;  instructions for the cross member at top
	  ;  instructions for the down stroke to curved part
	  half-circle height * .8
	  ;  closing instructions (if any)
	end

	to drawP [x y height]
	  ;  instructions for positioning the turtle
	  ;  instructions for the down stroke
	  ;  instructions before the curved part
	  half-circle height * .8
	  ;  closing instructions (if any)
	end

	to drawE [x y height]
	  ;  instructions for drawing the  E
	end

	to half-circle [height]
	  ;  set to work with 50 as the max x & y coordinates and patch-size of 5
	  repeat 20
	  [ fd height / 22.8
	    rt 360 / 36
	  ]
	end

Grading

As with the Scratch programming the TARR (task-specific activity and program report) document you submit will be the graded component of this assignment. Please keep in mind that the activity report should indicate what you did/included in your program, difficulties you had, your reaction, etc.—facts about the experience. The TARR document also includes a number of cues you can use to kickstart your reflection which is to include analysis of the experience and conclusions and rationales for them. The submission message should have the subject PEEE_Logo-I.

Extra Credit

You may submit programs for extra credit but all three must be submitted and each of them must work for any extra credit to be awarded.

If you have questions or difficulties

If you have questions about the assignment send me an e-mail or drop by my office. If you have a question while working on the assignment do the same. Keep in mind that when you encounter something you can't figure out you can/should think, explore, seek answers on google, etc. but, do not spend more than 15-30 minutes trying to overcome a particular error or problem.