How To Draw A Triangle In Msw Logo

UT Dallas Computer Science Outreach

A Program is a set of instructions to the computer to do a specific task

LOGO ����������� is the graphical programming language to move a �turtle� over the surface

Turtle Basics

The little triangle in the middle of the screen is called �turtle�.

�Moving the Turtle: FD 100

�

Turning the Turtle:

Getting Started!

We use the web based Logo Interpreter from http://www.calormen.com/logo/

The website stores your session history and saves your procedures to be re-used.

Command box in the bottom of the page looks like this:

You can issue the following commands and see them in action!

Basic Logo Commands:

Command	What it does
FD 100	Move the turtle forward 100 steps.
RT 90	Turn the turtle to the right 90�.
LT 90	Turn the turtle to the left 90�.
BK 100	Move the turtle backwards 100 steps.
PU	Put the turtle's pen up off the paper.
PD	Put the turtle pen back down on the paper.
CS	Clear the screen and start over.
HT	Hide the turtle (triangle).
ST	Show the turtle (triangle).
REPEAT 3 [...]	Repeat the commands 3 times.
HOME	Resets the turtle to centre of the screen
SETXY 20 20	Sets position of turtle to new values of X and Y
ARC 90 50	Creates arc enclosed in angle 90 with radius 50

1. Simple Drawings:

Issue the following commands and see the output. Try to understand why each command draws corresponding outputs.

Command	Output
cs fd 100 rt 90 fd 100 rt 90 fd 100 rt 90 fd 100
cs fd 100 rt 120 fd 100 rt 120 fd 100
cs rt 90 fd 100 rt 120 fd 100 rt 120 fd 100
cs lt 30 fd 100 rt 120 fd 100 rt 120 fd 100
cs fd 100 rt 90 fd 110 rt 90 fd 120 rt 90 fd 130

You can click ON the arrow at the top right corner (as shown below):

Now, you are in Command mode - you can type several commands in the window, but the program will run only when you click on Run button. Program continues to stay there � makes it easy to edit, update and run again. Try the commands for Simple drawings again:

2. Power of Repeat: Drawing Polygons and Stars

Use cs command to clear the screen whenever you want to start with a blank workspace.

REPEAT 3 [FD 100 RT 120]
REPEAT 4 [FD 100 RT 90]
REPEAT 4 [ FD 100 LT 120 FD 100 LT 120 FD 100 LT 120 FD 100 RT 90 ]
REPEAT 360 [FD 1 RT 1]
REPEAT 5 [FD 100 RT 144]

                      3. Try to draw these on your own!                                            

          End position of turtle can be anywhere & need not match with these drawings.                  

          Hints: you may need            pu            and            pd            commands to draw disconnected components. Also, you may also need repeat within repeat to draw complex stuff.                              

A	B	C	D
E	F	G	H
I	J	K	L

          Feel free to be creative and develop a few cool shapes on your own!                  

                      4. arc function to draw circle OR part of a circle.                              

          Note: Turtle does not move.                  

                      5. Try to draw these on your own!                              

                      6. set pen size and fill              color                                            

                      7. Let your creativity run wild and try a few              colored              picures              of your own!                              

                      8. random function                              

                      9. Logo Variables                              

          print :variable        

          can be used to print the values on screen.        

cs setpensize 2 make "angle 0 repeat 10 [fd 50 rt :angle make "angle :angle + 7]
cs setpensize 2 make "angle 0 repeat 45 [fd 50 rt :angle make "angle :angle + 7]
cs setpensize 2 make "angle 0 repeat 500 [fd 5 rt :angle make "angle :angle + 7]
cs pu setpensize 2 setxy -200 -100 repeat 4 [ pu fd 250 setcolor random 16 pd arc 360 random 150 fill rt 90 ]
cs make "angle 0 repeat 25 [ setpencolor random 16 fd :angle back :angle rt :angle make "angle :angle + 7 ]
cs repeat 20 [ �� setcolor random 16 �� setpensize random 5 � make "side random 200 � repeat 4 [fd :side rt 90] � rt random 360 ]
cs make "size 250 setpensize 1 repeat 10 [ � setpencolor random 16 � arc 360 :size � make "size :size - 20 � fill ]
cs make "size 10 repeat 50 [ � fd :size � rt 90 ��make "size :size + 5 ]
cs make "size 10 repeat 60 [ � fd :size � rt 120 � make "size :size + 7 ]
cs rt 90 setpensize 2 setpencolor random 16 make "size 1 repeat 60 [ ����� arc 180 :size ����� pu bk 4 pd ����� rt 180 ����� make "size :size + 4 ]
cs setpensize 2 setpencolor random 16 make "turn 0 while :turn < 360 [ �make "angle 0 � while :angle < 180 [ ��� fd 30 ��� rt :angle ��� make "angle :angle + 5 � ] � pu home pd � make "turn :turn + 60 � rt :turn ]
cs setpensize 2 make "turn 0 while :turn < 360 [ � setpencolor random 16 � make "angle 0 � while :angle < 180 [ ��� fd 20 ��� rt :angle ��� make "angle :angle + 5 � ] � �� pu home pd � lt :turn ��� make "angle 0 � while :angle < 180 [ ��� fd 20 ��� lt :angle ��� make "angle :angle + 5 � ] � pu home pd � ��make "turn :turn + 120 � rt :turn ]

                      10. Create your own artistic creations using the power of Variables!                              

                      11. Our own Procedures                              

          - We can write our own procedures in Logo, then use them like in-built functions!                  

TO SQUARE REPEAT 4 [FD 100 RT 90] END REPEAT 20 [SQUARE RT 20]
to square :size ����� repeat 4 [fd :size rt 90] end cs repeat 36 [square 100 rt 10]
cs make "size 200 repeat 36 [ � square :size �� rt 10 ��make "size :size - 5 ]
cs make "size 200 setpensize 2 repeat 36 [ � setpencolor random 16 � square :size �� rt 10 ��make "size :size - 5 ]
cs make "size 200 setpensize 2 setpencolor random 16 while :size > 0 [ � square :size �� rt 10 ��make "size :size - 2 ]
to triangle :size ����� repeat 3 [fd :size rt 120] end cs setpensize 2 setpencolor random 16 pu setxy 25 0 pd make "size 200 while :size > 0 [ � triangle :size �� rt 10 ��make "size :size - 20 ] pu home setxy -25 0 pd lt 60 make "size 200 while :size > 0 [ � triangle :size �� lt 10 ��make "size :size - 20 ]
to circle :radius ��arc 360 :radius end make "rad 200 cs setpensize 2 while :rad > 0 [ � setpencolor random 16 ��circle :rad ��make "rad :rad - 20 ] (or) to circle :radius ��if :radius > 3 [ ����� arc 360 :radius ��] end make "rad 200 cs setpensize 2 repeat 1000 [ � setpencolor random 16 ��circle :rad ��make "rad :rad - 20 ]
to star :size � repeat 5 [fd :size rt 144]���� END cs home make "size 40 while :size > 1 [ � pu fd 50 rt random 360 pd � setpencolor random 16 � star :size � make "size :size - 1 ]
to star � make "size random 40 � repeat 5 [fd :size rt 144]���� END cs home repeat 100 [ � pu fd 50 rt random 360 pd � setpencolor random 16 � star ]
to star � make "size 20 + random 20 � repeat 5 [fd :size rt 144]���� END cs home window repeat 100 [ � pu fd 50 + random 50 rt random 360 pd � setpencolor random 16 � star ]
Utilize the following procedures to draw these images and more... to circle :dist � repeat 360 [fd :dist rt 1] end TO circles :count :dist � repeat :count [ ����circle :dist �� � rt 360 / :count � ] end pd setpensize 2 ...

                      12. Write your own procedures and use them in interesting ways!                              

                      13. Recursion                              

                      Click on�              Examples in                                http://www.calormen.com/logo/#                                and see last 2: fern & tree                              

to drawPattern :level � if :level > 0 [ ��� make "level :level - 1 ��� fd 50 ��� lt 60 ��� drawPattern :level ��� rt 120 ��� drawPattern :level ��� lt 60 ��� bk 50 � ] end cs window setpensize 2 drawPattern 3 Change the argument for drawPattern to higher � �� �� �� �� values and see the action! �window� command � �� �� �� �� ensures that the drawing does not wrap around and � �� �� �� �� appear near the opposite edge. �
to drawPattern :level � if :level > 0 [ ��� make "level :level - 1 ��� fd 50 ��� lt 60 ��� if :level > random 10 [ �� �� � drawPattern :level ��� ] ��� rt 120 ��� if :level > random 10 [ ��� � drawPattern :level ��� ] ��� lt 60 ��� bk 50 � ] end cs window setpensize 2 drawPattern 10 � Draws a random pattern every time you run! How?
to tree :level :size � if :level > 0 [ ��� fd :size ��� lt 10 ��� tree :level - 1 :size * 0.8 ��� rt 10 ��� rt 30 ��� tree :level - 1 :size * 0.8 ��� lt 30 ��� pu bk :size pd � ] end cs window pu setxy 0 -200 pd setpensize 1 tree 13 100
to tree :level :size � if :level > 0 [ ��� fd :size ��� lt 20 ��� tree :level - 2 :size * 0.7 ��� rt 20 ��� rt 20 ��� tree :level - 1 :size * 0.9 ��� lt 20 ��� pu bk :size pd � ] end cs pu setxy -100 -200 pd setpensize 1 tree 20 100
to tree :level :size � if :level > 0 [ ��� setpensize :level ��� fd :size ��� lt 20 ��� tree :level - 2 :size * 0.7 ��� rt 20 ��� rt 20 ��� tree :level - 1 :size * 0.9 ��� lt 20 � �� pu bk :size pd � ] end cs pu setxy -100 -225 pd setpensize 1 tree 15 100
make "angle1 15 make "angle2 30 make "factor1 0.9 make "factor2 0.8 to tree :level :size � if :level > 0 [ ��� setpensize 1 + :level / 3 ��� if :level < 3 [ ����� setpencolor 10 ��� ] ��� if :level >= 3 [ ����� setpencolor 0 ��� ] ��� fd :size ��� lt :angle1 ��� tree :level - 1 :size * :factor1 ��� rt :angle1 ��� rt :angle2 ��� tree :level - 1 :size * :factor2 ��� lt :angle2 ��� pu bk :size pd � ] end � cs window pu setxy 0 -200 pd tree 13 70 Make changes to angle1, angle2, factor1 and factor2 to make your own wonderful tree!
make "maxlevel 13 to tree :level :size :turn � if :level > 0 [ ��� fd :size ��� lt :turn ��� tree :level - 1 :size * 0.9 :turn - 3 ��� rt � :turn ��� rt :turn ��� tree :level - 1 :size * 0.9 :turn - 3 ��� lt :turn ��� pu bk :size pd � ] end cs window pu setxy 0 -250 pd setpensize 1 tree :maxlevel 75 25
TO recSquare :level :size � if :level < 1 [ stop ] � repeat 4 [ ��� setpencolor :level ��� fd :size ��� recSquare :level - 1 :size / 2 ��� rt 90 � ] end cs recSquare 2 150 Play with different levels! Also, how will you change the colors & fix the tilt.
Koch Curve to kochCurve :level :size � if :level < 1 [ fd :size stop ] � kochCurve :level - 1 :size / 3 � lt 60 � kochCurve :level - 1 :size / 3 � rt 120 � kochCurve :level - 1 :size / 3 � lt 60 � kochCurve :level - 1 :size / 3 end cs kochCurve 4 300 Play with different levels (instead of 4) to understand what is going on.	level = 0 level = 1 level = 2 level = 3 level = 4
Now let your creativity run wild and build various drawings using Koch Curve as a building block.	� � �

                      14. A few more interesting drawings ...                                            

          Feel free to put a personal touch!                  

                      15. More built-in functions...                              

          Now that you have played with lots of examples, click on References in                    http://www.calormen.com/logo/                    and select an interesting one to come up with a cool drawing on your own!                              

How To Draw A Triangle In Msw Logo

Source: https://utdallas.edu/~veerasam/logo/

Posted by: jolleycapecontabir.blogspot.com

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