LOGO Language Instructions
by R. Barrett and B. DeRoos
THREE (3) SPECIAL WORK AREAS IN LOGO:
1. The TURTLE SCREEN or Play Pen (Graphics Area) where the
turtle draws with a pen taped
to his middle. PRINTSCREEN gives a hard copy of this graphics
area.
2. The COMMAND CENTER under the Play Pen. Use [Ctrl]U to go to the Play Pen
and or
[Ctrl]D to return to Command Center. You issue commands in the
Command Center like FD 50 to go forward 50 steps
or NPE "______ to save the playpen and the flip page.
3. The PROCEDURE SCREEN
of "Flip Side" i.e. the Turtle's memory. To go to Flip Side
press [Ctrl] F and use the same keys to return to the play pen
page. You put or write
procedures here like TO BOX below. Then you can use the
procedure in the Command
Center by typing BOX. Use PRINTTEXT from the Command Center
under the PROCEDURE
SCREEN to print out procedures. When you turn off the computer
or get out of LOGO, you
lose all the commands in the Command Center. Only procedures and
the pictures in the
Play Pen are saved when the page is save. So I call the
procedure page the Turtle's Mind
because you can teach turtle things to do here and he will
remember.
TWO (2) SPECIAL SCREENS IN LOGO:
1. The TITLE SCREEN which you see when you first get into
LOGO.
2. The LOGO selection screen or SCRAPBOOK which allows you to
recall
previous work or to design new pictures/text on a NEW PAGE. The
Scrapbook
organizes by Page Name all your turtle drawings, & the recipes or
procedures. LOGO saves the Play Pen and the Procedures with the
NP
"filename command. The [Esc] key takes you from a work page
back to the
Scrapbook.
TWO (2) TURTLE SPEEDS:
1. Star War's Warp or light speed where the turtle goes too fast
to
follow. This is the default speed or Fast Speed. To get back to
this
speed the command is FASTTURTLE
2. Slow speed where the turtle crawls around the screen. This
speed is
great when you are "playing turtle". "Play Turtle" is a problem
solving
technique that Seymore Papert suggests for solving problems.
"Just think
how the turtle would have to move to draw what you want!", Papert
would
say. SLOWTURTLE is the command for this speed.
SPECIAL KEYS:
[Esc] 
Escape to get back to the
Scrapbook screen.
[Ctrl][Pause] STOP a turtle trip or a
calculation.
[Ctrl]F FLIP to the FLIP or PROCEDURE
screen.
[Ctrl]U To put cursor into the Play Pen
for labeling or
adding text
[Ctrl]D To go DOWN to COMMAND TABLET
from Play Pen
[Ins] To get a fresh line on the
Command Center
SYSTEM COMMANDS:
NP "___ Name Page for saving. (Use an 8
letter name.) You must do this before you can get out of
LOGO.
DOS Return to DOS; get out of LOGO
PRINTSCREEN Prints what is visible on the
turtle Play Pen
PRINTTEXT Prints TEXT only. To print out
PROCEDURES, flip to the procedure Page, use [Ctrl]D to get to the
Command Center. Type PRINTTEXT.
NEWPAGE If you have already named the current
page, this command save the currently page and starts you on a
new page.
ERPAGE "___ ERase PAGE erases the page named
from the
scrapbook saved on
disk.
COMMANDS:
RG Reset or Clear Graphics
CC Clear Command Center
CG Clear Graphics
CT Clears TEXT in the TURTLE TABLET
RT __ Right Turn (Degrees)
LT __ Left Turn (Degrees)
FD __ Forward (Turtle Steps)
BK __ Back Up (Turtle Steps)
REPEAT __ [ commands ] (Number of Repeats) Command to Repeat Commands
PE Pen Erase removes a line that turtle
covers.
PU Pen Up turtle does not make a line
PD Pen Down turtle draws and the STAMP
command works
HT Hide Turtle
ST Show Turtle (opposite of Hide Turtle)
PRINT [_______] Puts TEXT on the Play Pen
with CARRIAGE RETURN
RANDOM nn Selects an Unexpected NUMBER from 0
TO nn
SETBG __ Choose a Color 1 to 8:
| NUMBER | 1 | 2 | 3 | 4 |
5 | 6 | 7 | 8 |
|---|
| COLOR | BLUE | PURPLE | WHITE |
RED | PURPLE | TAN | BLACK |
GREY |
|---|
SETC nn Set or Change Turtle's COLOR and
color of lines;
use a
number 1 to 15
SETSH nn Set SHAPE. Choose from 35 or more
shapes see TABLE below.
SHAPES Shows SHAPES and their NUMBERS;
to return to Command Center. When you type this command you can
create or edit sprites or shapes. They will be automatically
saved in the shapes file.
STAMP Prints SHAPE of TURTLE on SCREEN &
LEAVES it there!
TONE fff dd Sounds a NOTE of FREQUENCY fff
and DURATION dd (See table).
MATH COMMANDS:
A variable when defined has a (Quotation Mark) in Front "X but
when used
it has (Colon) in Front :X Variables DO NOT have default
VALUES. They
must be defined before use!
MAKE "C 10 Assigns or defines C as 10.
MAKE "X :X + 1 Is Counting
IF___ [____] IF comparison [ commands ]
e.g. IF :X > 10 [STOP]
SHAPE TABLE:
MUSIC NOTES:
| NOTE | C | C# | D | D# |
E | F | F# | G | G# | A |
A# | B |
|---|
| FREQUENCY |
523 | 554 | 587 | 622 | 659 |
698 | 740 | 784 | 830 | 880 |
932 | 988 |
|---|
A rest is TONE 0 5
PROCEDURES:
Must be typed on the FLIP page using F,
they must start with an infinitive like TO BOX (no spaces in
procedure
name), and
they must end with an END on a separate line. Examples below:
TO STAR 
Draw a STAR
REPEAT 12 [FD 100 RT 160]
END
TO C Play the note C with a duration of 10
TONE 523 10 To actually sound this note type
C at the command line
END
TO CIRCLE Draw a CIRCLE
REPEAT 36 [FD 5 RT 10] The RT angle and the
number of repeats must be 360 for a full circle
END
TO FLOWER
REPEAT 10 [RT 36 CIRCLE] 36x10 = 360 for a
full flower
END
TO BOX Draw a BOX
REPEAT 4 [FD 50 RT 90]
END
To
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