Papert―logo in your browser
I came across this site a year or so ago and really enjoyed using it to discover and draw various well-known fractals.
Here are a few programs I made with it. For some reason I tried to write them in a pure-ish functional style, accepting that the turtle has to move and turn but avoiding the "cheat" commands like setxy (placing the turtle at an absolute position) or make (setting a variable). Note that the default is to 'run normally'. You might want to click 'stop program' and then 'run fast'.
* Sierpinski triangle: http://logo.twentygototen.org/83EGZPPC
* Sierpinski carpet: http://logo.twentygototen.org/4c5iy9iU
* Sierpinski arrowhead curve: http://logo.twentygototen.org/hYDSZt8h
* Hilbert curve: http://logo.twentygototen.org/CFyUSzqG
* Hexaflake: http://logo.twentygototen.org/AJeuVkKc
Wow. Just wow. Brought back memories from elementary school! I totally despised my computer class where we were taught logo. During the exam I walked in completely clueless. Not knowing anything and having tonnes of time in front of the screen, I started typing some commonsense words and numbers and BOOM! stuff started showing up on my screen. I passed the exam--thanks for the geniuses who made a truly simple language an idiot kid could figure out!
It is available on google code: http://code.google.com/p/papert
It is also in some serious need of attention after being plagued by spambots.
If anyone fancies hacking on it I will happily add them to the svn repository/google app engine.
This is depressing. I spent the last 3 nights working on this same idea, except it was closer to Python's turtle module than Logo, and it used Google's Closure library.
Oh well, I'll continue on.
It seems like I've run across a couple implementations of Logo in javascript recently. Here's another:
And, here's one that uses svg instead of canvas:
http://www.amberfrog.com/logo/
I think it'd be a lot of fun to do webapp for creating and sharing artwork made in Logo -- with a bunch of github-like social features. Or, maybe Facebook integration?
Logo was my favorite thing about 4th and 5th grade, and I've not touched Logo code since then. Having not touched it in the 25-odd intervening years, my memories of struggling to hold a whole program design in my head are relatively clear; and it is amazing how much easier programming is now. Something to remember if my kids start wanting me to teach them to program a couple of years from now.