Learn to write computer programs with us in 15 minutes!
You can try this here or you can take these instructions with you and try this out in the quiet and privacy of your own home :-)
Imagine you're giving instructions to someone to pace out a shape on the floor.  You can tell them to walk forward so many paces, or walk backwards instead, and turn left or right.  Now the 'person' we're asking this of is actually a little turtle with tiny little legs, so to go a reasonable distance we ask him to walk 100 little paces...
Here are the commands you can give him:
FORWARD 100   - that means walk forward 100 paces
RIGHT 90            - turn to the right (90 degrees)
BACKWARD 100 - walk backwards 100 paces
LEFT 90               - turn to the left (90 degrees)
RIGHT (or LEFT) 180 - turn about and face the way he just came
So how do you tell our pet turtle to pace out the shape of a square on the floor?
FORWARD 100
RIGHT 90
FORWARD 100
RIGHT 90
FORWARD 100
RIGHT 90
FORWARD 100
RIGHT 90
- and bingo, he's back to exactly where he started.  Try this on our web page and see what happens.  (www.gtoal.com/easilogo)
Well, that was a lot of typing and a bit repetitive, so we have a way of asking the turtle to repeat the same instructions over and over, however many times we want.  We say:
REPEAT 4 [
   FORWARD 100
   RIGHT 90
]
Saying this is identical to what we said before... try it...
Here's a trick you'll find handy - it's just a way of typing less.  Instead of typing "FORWARD", just type "FW".  For BACK you can say BK and you can abbreviate LEFT and RIGHT as LT and RT.  And although it may be less readable, you can put these instructions all on a single line.  This will save you a lot of typing and let me squeeze more examples into the page! 
That last example looks like this, when we use the shorthand version:   REPEAT 4 [ FW 100 RT 90 ]
Well, we've now taught the turtle how to pace out the shape of a square, but we've just had him do it once, and he's a silly little turtle and he's already forgotten what we've taught him, so we need a way to teach him to remember how to make a square so that in the future we can just ask him to make a square and not have to spell it out in detail again like he's an idiot!   We say...

TO SQUARE
  REPEAT 4 [  FW 100 RT 90 ]
END
and now that he's learned how to make a square, we'll get him to make one by just asking...
SQUARE
and yes, he does it right!  Whee!
Let's see if we can do something more complicated just by asking our turtle to draw squares...  can you guess what this will draw?
REPEAT 4 [ SQUARE RT 90 ]
If you're not sure, try pacing it out on the floor...
Now we're getting somewhere!  Try typing this line, it's very similar except for one small detail...
REPEAT 5 [ SQUARE RIGHT 360/5 ]
(remember that 360 degrees is one complete turn... so we're asking him to make a fifth of a turn between making each square, instead of a quarter turn which is what "RIGHT 90" really was...)
That was fun, we're starting to make pretty pictures!
What I want to do next is ask our turtle to draw different sizes of squares.  So we tell him, "when I explain to you how to make a square, instead of pacing out 100 steps on each side, I want you to pace out however many steps I ask you to do and make a different size of square"... Like this...
TO SQUARE :steps
   REPEAT 4 [ FORWARD :steps RIGHT 90 ]
END
OK, so let's ask for a smaller square...  let's say 50 steps on a side...
SQUARE 50
Yay!  That worked!  Let's use that and draw something fancier...
SQUARE 25
SQUARE 50
SQUARE 75
SQUARE 100
OK, that's nice, but we're repeating ourselves again.  Didn't we have a way to tell the turtle to repeat things?  Except the size of the square changes each time so it's not quite the same thing we're repeating - how do we handle that?
We need some way to allow numbers to change.... let's give them a name and use the name instead...
MAKE "steps 25
REPEAT 4 [
   SQUARE :steps
   MAKE "steps :steps + 25
]
You're probably thinking that all these funny characters like " and : are weird and confusing.  Well, yes, they are, it's just one of those things that computers need, that you just have to live with.  But just copy what we do here and you'll be fine.  The computer will usually tell you if you've forgotten one of those silly characters.
So with that last trick we just learned (the things that remember numbers are called "variables" because the number that they're remembering for you varies every time you add another 25 steps to it), you now know enough to write some pretty advanced computer programs!
On the remainder of this worksheet are some example programs that Marcio prepared for you.  You should find them familiar by now and they're all pretty similar to what we've learned here already.
Once you've got a nice drawing on the web page, show me your program and I'll run it on the Etch-a-Sketch for you.

Etch-A-Sketch Interactive LOGO - 'EASiLOGO'!
You've just learned how to program in a language called LOGO which was invented in the 1970's as a way to teach children about computer programming.  Back then they used a robot that looked like a turtle to do the drawing, but we're going to use a very similar system with an Etch-a-Sketch instead.  You don't need the actual Etch-a-Sketch to try this - we have a web page with software that looks just like an Etch-a-Sketch that will work just as nicely!
Turn the last page and you'll find some logo programs that you can try which will draw pictures on the Etch-a-Sketch.

We can draw a star:
TO STAR :size
         REPEAT 5 [FW :size RT 360/5]
END
STAR 30
Or a square:
TO SQUARE :length
         REPEAT 4 [FW :length RT 360/4]
END
SQUARE :10
If you look at the last two shapes and see what they have in common, you can make all sorts of polygon shapes using the same sort of instructions...
TO POLYGON :length :sides
         REPEAT :sides [FW :length RT 360/:sides]
END
POLYGON 5 10
We can use the variables we learned about to make cool spirals...
TO SPIRAL :angle :length :increase
        REPEAT 400 [
                  FW :length RT :angle
                  MAKE "length   :length + :increase
         ]
END
SPIRAL 119 1 3