KTurtle/C3/Grammar-of-TurtleScript-Part-II/English-timed
From Script | Spoken-Tutorial
| Visual Cue | Narration
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| 00.01 | Hi everyone,
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| 00.02 | Welcome to the tutorial on Grammar of Turtle Script-Part II. |
| 00.06 | If this is the first time you are using KTurtle, please view the
tutorial introduction to KTurtle
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| 00.11 | which will help you understand the installation and interface of the
application and some of the basic commands to move the turtle.
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| 00.18 | Also view the tutorial Grammar of Turtle Script-Part I,
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| 00.22 | to understand few more commands that are used in the Kturtle environment.
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| 00.26 | These tutorials can be viewed on the spoken tutorial website |
| 00.31 | This tutorial will introduce some more commands to be used in the KTurtle environment.
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| 00.36 | We will learn the
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| 00.37 | learn command
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| 00.39 | And the random command
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| 00.40 | For this demonstration, I am using the Linux Operating System Ubuntu
v11.04,and Kturtle v0.8.1 beta.
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| 00.51 | Let us first look at the learn command.
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| 00.54 | learn is special as it is used to create your own commands. |
| 00.58 | The commands you create can take input and return output.
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| 01.02 | Let us take a look at how a new command is created. |
| 01.06 | I will launch the Kturtle application
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| 01.11 | And Let us enter the following lines of code in the editor to draw a
square:
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| 01.33 | here the number 10 specfies the length of the side of the square.
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| 01.40 | Now let us learn the commands involved to draw a square using the 'command 'learn .
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| 01.46 | We will name this set of commands to draw a square as square.
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| 01.53 | The command learn is followed by the name of the command to be learnt,
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| 01.58 | in this case it is square.
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| 02.01 | So i will enter the command learn before square
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| 02.24 | so here the new command that we have defined is called square. |
| 02.30 | square takes one input argument, i.e $x to set the size of the square.
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| 02.36 | One important point to be noted here is, |
| 02.39 | when you run this piece of code, It does not return no output.
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| 02.45 | The command learn is just 'learning' the other command
square to be used later.
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| 02.51 | The square command can now be used like a normal command in the rest of the code.
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| 02.57 | Let me add few more lines of code here.
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| Type the following code in your editor:
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| 03.09 | Let me select Run from the toolbar to run this piece of code from the editor.
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| 03.15 | The turtle now draws the square on the canvas.
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| 03.18 | The command square can now be used anywhere and any number of times in the program .
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| 03.27 | Also Note that this command can be used only within the scope of this program.
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| 03.30 | Let us next look at the 'random' Command.'
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| 03.34 | random is a command that takes input and gives output.
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| 03.38 | The syntax for this command is random X,Y
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| 03.42 | where X and Y are two inputs. |
| 03.44 | X sets the minimum output and Y sets the maximum.
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| 03.49 | The output is a randomly chosen number between X and Y.
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| 03.54 | Let us put the random command to use in the application.
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| 03.59 | In my editor, I will enter a few lines of code to draw a circle.
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| 04.29 | Here, the command random 1,20 selects a random number which is equal or greater than 1 and equal or lesser than 20,
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| 04.41 | and assigns it to the variable x.
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| 04.44 | When you run this piece of code, a circle with a radius of size, which is in between 1 and 20 is drawn on the canvas.
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| 04.53 | Let us execute this code a few times, and you can see that a circle with a different size is generated each time.
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| 05.06 | Every time you execute this code, a circle with a different radius is drawn.
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| 05.13 | Let us now use both the learn and random commands in an
example.
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| 05.24 | Here, i have with me few line of code that demonstrates the use of both the learn and the random command.
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| 05.31 | i am going to copy the entire code on to my clipboard and paste it in my editor in the Kturtle application.
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| 05.46 | Let us see what each line means here.
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| 05.50 | canvassize 300,300' sets the width and height of the canvas to 300
pixels each.
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| 05.58 | $R, $G, and $B are three variables to which I am
assigning random values between 0 and 255.
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| 06.07 | In the command 'canvascolor $R,$G,$B' ,
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| 06.11 | the Red-Green-Blue combination is replaced by the values assigned to the variables R, G, and B in the previous step.
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| 06.20 | The canvas color is now set randomly when this command is executed.
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| 06.27 | $red, $blue, $green are another set of variables
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| 06.33 | to which values between 0 and 255 are assigned randomly.
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| 06.38 | Again in the command 'pencolor $red,$blue,$green' the
Red-Green-Blue combination values are replaced by the variables
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| 06.48 | $red, $green and $blue to which random values are assigned in the previous step.
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| 06.53 | The color of the pen is also set randomly when the command is executed.
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| 06.57 | 'penwidth 2' sets the width of the pen to 2 pixels.
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| 07.02 | I have next entered the code to learn to draw a circle.
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| 07.08 | Here $x represents the size of the circle.
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| 07.12 | The next set of commands i.e the go commands |
| 07.16 | followed by the circle commands draws circles with the specified sizes.
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| 07.23 | For example the command circle 5 draws a circle of size 5
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| 07.28 | If the co-ordinates X and Y specified in the go commands.
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| 07.33 | For each circle, I have specified different positions on the canvas.
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| 07.39 | Let us execute this code now.
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| 07.42 | I am going to run this execution at full speed.
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| 07.46 | But you can select any of the speeds mentioned in the Run option.
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| 07.52 | I will run this code few more times, so that you can see the difference in the randomly set values of pen color and canvas color.
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| 08.06 | When I execute the code one more time, note the change in the color in the pen and the canvas.
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| 08.19 | You can exceute this code how many ever times you want and you can note the change in the randomly set values.
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| 08.31 | As an assignment for you to solve,
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| 08.33 | using the learn command,
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| 08.35 | draw a pentagon, a square, a rectangle, a hexagon on the four corners of your canvas
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| 08.43 | and a circle at the centre of the canvas.
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| 08.47 | Using the random command create various colors and customize the shapes and also the canvas.
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| 08.55 | I have created my own customized canvas for the geometric shapes,
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| 09.00 | and your assignment should look some thinglike this.
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| 09.03 | Let me run the piece of code in the application.
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| 09.09 | You can see the geometric shapes and the color of the canvas changing each time.
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| 09.17 | I would like to acknowledge the spoken tutorial project |
| 09.20 | which is part of the talk to a teacher project.
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| 09.23 | Supported by the National Mission on Education through ICT, MHRD
Government of India.
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| 09.28 | For more information please visit the link shown on the screen.
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| 09.33 | The video on the link shown summaries the spoken tutorial project.
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| 09.37 | If you do not have good bandwidth, you can download and watch it. |
| 09.41 | We also give certificate for those who pass an online test. please
contact us contact@spoken-tutorial.org for more details . |
| 09.48 | Thank You.This is Sindhu signing off. Enjoy playing with KTurtle!
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