Logo

Welcome to Logo!

Update 2013: see turtlebits.com, my new turtle environment.

Get started with Logo here.

Be sure to press the button below at least once before leaving this page, or else you will see a Turtle Tracks bug.

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1. Start Logo

Press the button.

Move the window so you can read this page.

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2. Draw the Turtle

In the new window, type "draw", and press Enter.

Move the black window so you can see where to type.

The triangle is your turtle.

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3. Move the Turtle

Here is how to move the turtle.

fd 80	moves forward 80 little steps
rt 45	turns right 45 degrees
fd 71	moves forward 71 little steps
lt 90	turns left 90 degrees
bk 71	backs up by 71 little steps
rt 45 bk 80 lt 90 fd 100	does things fast - what did you draw?
cs	clears the screen again

Move the turtle around some more.

Have fun!

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4. Tell the Turtle to repeat

What do you think this draws?

fd 100 rt 120 fd 100 rt 120 fd 100 rt 120

You can tell the Turtle just to repeat:

repeat 3 [ fd 100 rt 120 ]

Press the up-arrow to edit the same line again.

Change the numbers.

repeat 8 [ fd 50 rt 45 ]

What did you draw?

Can you make a square? A circle?

This one is fancy:

repeat 36 [ repeat 36 [ fd 10 rt 10 ] rt 10 ]

You can repeat repeats.

What can you make?

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5. Teach the Turtle a word

The turtle can learn new words.

To teach it "square", type

to square (and press Enter)
repeat 4 [ fd 100 rt 90 ] (press Enter)
end (press Enter)

The Turtle hasn't drawn anything. It says "square defined".

Now type "square" and press Enter.

What happened?

Try "repeat 10 [ square rt 36 ]"

Why did it draw that?

Do you have other words you want to teach the Turtle?

Teach the Turtle your own words.

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Links

My friend Mike Koss has some good Logo worksheets at mckoss.com/logo.

On this webpage I am using Turtle Tracks because it works from a web browser and I do not need to install anything extra on classroom computers. Turtle Tracks was writen in Java by Daniel Azuma. You can find the manual at turtletracks.sourceforge.net/docs.

The Logo language was invented by Seymour Papert at MIT. Turtle Tracks is a dialect of Berkeley Logo by Brian Harvey. A very complete manual for Berkely logo can be found at www.cs.berkeley.edu/~bh/docs/html/usermanual.html