A GUIDE TO USING MSW LOGO 

This program enables you to write commands and tell the computer what to do. The simplest use is to move an arrow around the screen to draw shapes or to move a turtle through an obstacle course on the floor.  
TO MOVE THE ARROW:  BACK n 
to move the pen backward in the opposite direction to the
arrow by <n> spaces, eg. BACK 15, BK 15 or BK :side FORWARD n  to move the pen forward in the direction of the arrow by <n> spaces, eg. FORWARD 20, FD 20 or FD :side LEFT n  to turn the arrow through <n> degrees to the left, eg. LEFT 90, LT 90 or LT :angle RIGHT n  to turn the arrow through <n> degrees to the right, eg. RIGHT 120, RT 120 or RT :angle 
TOOLS:  CLEARSCREEN
or CS  to clear the screen and return the arrow to the
centre of the screen. PENUP or PU  to lift the pen off the paper PENDOWN or PD  to put the pen down PENERASE or PE  to erase as it moves PENPAINT or PPT  to stop erasing mode (default) SETPENCOLOR [r g b]  where r,g & b is the intensity of each primary colour ranging from 0 to 255 (default = 0 0 0 for black), eg. [255 0 0] is red, [0 255 0] is green, [255 255 0] is yellow (red+green). SETPENSIZE [w h]  where w is the width and h is the height (default = 1), eg SETPENSIZE [2 2] will double the line width. 
PROCEDURES:  Select File/Edit
from the menu and either type a name for a new procedure
or select an existing procedure from the list provided.
This brings up an editing screen showing, for example,
for a procedure called square: to SQUARE Typing the command SQUARE will then draw a square with length of side equal to 100. You have taught the computer a new word! 
REPEAT LOOPS:  To simplify a
repetitive task, the above procedure becomes: to SQUARE 
VARIABLES:  A letter or a word
following a colon (:) becomes a variable just like you
use the letters like a, b, n, x, or y in algebra. to SQUARE :a You must tell the computer what you want the value of the variable to be. Typing the command SQUARE 200 will then draw a square with length of side equal to 200 
ARITHMETIC:  The normal
arithmetical operations (+, , *, and /) can be performed
on variables. The above procedure could be changed to: to POLYGON :n :a Typing the command POLYGON 4 200 will also draw a square with length of side equal to 200, but now you can vary the number of sides with the variable :n 
Page last updated 23/05/2003 © Copyright, I.D.Lee,
Didcot Girls' School.
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