Tutorial

Brief Introduction

PiE (Programming in Eliza/English) is a tool that helps beginners to learn how to program. By interacting in Natural Language, currently we only can handle English, user can manipulate the "Turtle" (which is represented as an triangle in this design) on the canvas. The turtle will leave the trace wherever it goes and these traces will be a beautiful pattern.

Get in a dialogue with PiE

First Try

• Type in Can you forward 150 steps? and Click the Talk. See what happen?
• Great! The "turtle" just move forward 150 steps! And PiE confirmed your command in the response box.
• Then Type in Turn left 90 degrees! and Click the Talk. You can also type the Enter on the keyboard instead of the Click.
• You will then see the "turtle" turn left 90 degrees!
• Next, let's try move the turtle quicker and more fluently by using repeat.
• Type in Repeat last 2 commands for 3 times!.
• Yeah! You got a square! right?
• You can clear the screen by Clear the screen!

Move the turtle

• Basically, the turtle can move forward and backward. Try Go forward 150 steps! and Get back 150 Steps.
• Besides, staight move, the turtle can turn clockwise(right) or anti-clockwise(left). Try Turn left 90 degrees and Turn right 90 degrees. You can name any degree between 0 to 360. In addition, try Turn left. and Turn right. The turtle will by default turn 90 degrees.
• If you do not want the pattern any more, just Clear the screen!!

Attributes can be modified

• The turtle can draw with its movements. If you want to change how the trace looks like, please go on with this section.
• First, let's try to make the line bolder. Type in Can you use a bolder pen? and then try Go forward 100 steps!. How it look?
• Then, let's make the line lighter. Type in Use a lighter pen and try again Go forward 100 steps!. See the difference?
• You can also change the color of the line by Can you change to color red?. You can change to any other colors like: grey purple green yellow black blue red.
• Test with Forward 100 steps. Your turtle might hit the wall if you continued three 100 step forward. After it hit the wall, it will appear from the other side.
• Sometimes, you just want to move the turtle but not leave any traces. In this case, let's suspend the turtle.
• Suspend the turtle by Get up! and the turtle will be off the canvas. There will be no trace left when the turtle is off the paper. You can try Can you forward 50 steps? to double check.
• Put down the turtle by Get down!
• Test with Forward 100 steps

Basics in Programming

• In this section, we will tell you some basics in programming.

  Loop

• Loop is a faster way to get things done if you want to repeat several commands over and over again. Let's see how to use it.
• First, let's try these commands one by one. Forward 150 steps Turn left 90 degrees Forward 150 steps Turn left 90 degrees Forward 150 steps Turn left 90 degrees Forward 150 steps Turn left 90 degrees What do you get? A square! But how to use less commands to realize the same thing?
• Try these commands one by one
  Go forward 100 steps. Turn left can you repeat last 2 commands for 3 times?
• You see. We use 3 commands to draw a square instead of 8 commands.

  Function

• You can read this part after the next section "Write in Scripts".
• Function helps to reuse some capsulated commands. Try the following commands:

  Let's define a function called Square
    Repeat the following commands for 4 times
        Go forward 100 Steps        
        Turn left 90 degrees
    End the Repeat
  End the function
  Then Clear the screen
  Call the function square

  Turn right 60 degrees
  Again, Call the function square 

Write in Scripts

• You can write down a few sentences to manipulate the turtle at a time instead of being involved in the tedious dialogue. Take the square as an example. Try copy-paste the following commands in the Multi-line Mode by clicking on the arrow beside the Talk button.

Use a red pen
Let the pen be bolder
Repeat the following commands for 4 times
  Go forward 100 Steps
  Turn left 90 degrees
End the Repeat

• After the copy-paste, click on the Talk button. What do you get?
• You can revise the script in the Multi-line mode by adding or deleting in the box. Try add Repeat the following commands for 36 times after Let the pen be bolder and Turn left 10 degrees and End the repeat after the original End the Repeat. What do you get?

Use a red pen
Let the pen be bolder
Repeat the following commands for 36 times
  Repeat the following commands for 4 times
    Go forward 100 Steps
    Turn left 90 degrees
    End the first Repeat
  Turn left 10 degrees
End the second repeat

• What? Did not see it clearly. Let's try it step by step. In the third command, change "36" into 1, 2, 4, 8, 12, 16 respectively. Do you understand now?

Try More

Till Now, you are good with basics in programming and You can handle most cases in LOGO to draw any graphs. Don't believe it? Try the Examples!