Turtle Art

Turtle Art This activity was bundled sources in projects/turtleart-activity .xo Bundle – Turtle Art.xo TST Tickets all - active - new Localization .POT file NEEDED Brian Silverman see more templates or propose new

Turtle Art is an activity with a Logo-inspired graphical "turtle" that draws colorful art based on Scratch-like snap-together visual programming elements.

There are many restrictions compared to Logo. User defined procedures can't have parameters. Limited screen real-estate makes building large programs infeasible. Only simple variables are available, no lists or other data-structures.

There are five palettes of program elements available for program construction. Conditions for the If block are a different shape than numeric parameters used by the other blocks.

• Turtle (green)
  • Clear
  • Forward(n)
  • Back(n)
  • Left(angle)
  • Right(angle)
  • Arc(angle,radius)
  • SetXY(x,y)
  • SetH(heading)
  • Turtle state values (can plug into a parameter)
    • X, Y, heading
• Pen (cyan)
  • Pen Up
  • Pen Down
  • Set Pen Size(n)
  • Set Color(n)
  • Set Shade(n)
  • Fill Screen(color,shade)
  • Pen state values (can plug into a parameter)
    • Pen size, color, shade
• Numbers (violet)
  • Values (can plug into a parameter)
    • Number
    • Infix operators(left,right)
      • +, -, *, /, mod
    • Random(min, max)
  • Conditions (oval, plugs into an If block)
    • <, <, = (take two values)
    • and, or, not (take other conditions)
  • Print(n)
• Flow (orange)
  • Wait(n)
  • Forever[stack] (no continuation)
  • Repeat(n)[stack]
  • If(condition)[then]
  • If(condition)[then][else]
  • Stop (no continuation)
  • Connectors:
    • jog right
    • jog down
• My blocks (yellow)
  • Named stack - a rhombus which tops a stack, equivalent to a procedure definition (but without parameters).
  • "Stack" - blocks for invoking a named stack (no parameters)
  • Store in "box"(n) - blocks for setting a variable
  • "Box" (plugs into a parameter)
• My stuff (?)
  •  ? (no screenshot, and not in groups, but I see it in the source tree)
  • 1input, 1inputs, 3inputs: looks like invoking a stack with 1/2/3 parameters
  • boutput: looks like a blank condition
  • opwithlip, opwithlipb: looks like box parameters that can be chained (socket on right)

There are also some icons at the bottom right for user control:

• Show/Hide the turtle
• Eraser
• Stop (for infinite loops)

<gallery> Image:Turtle0.png|Turtle Art startup screen Image:Turtle1.png|Clicking on the Blocks menu brings the basic tool set into view Image:Turtle2.png|Drag blocks from the menu Image:Turtle3.png|Click on the top block of a stack to execute the stack Image:Turtle4.png|Other blocks can be found under the tabs Image:Turtle5.png| Image:Turtle6.png|Example projects are found on the Projects menu on the upper right of the screen Image:542-turtleart-2.png Image:Turtle-recursion-1.jpg|A recursive algorithm (difficult without parameters)

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