Blockly is a library from Google for building beginner-friendly
block-based programming languages.
It is a wonderful library that I was able to customize to by heart's content.
It has a well written code base and the people working on the project are
super helpful. If you want to add a visual-code editor to your application
Blockly is a great way to do it.
The Algorithmic Beauty of Plants is a book by Przemyslaw
Prusinkiewicz and Aristid Lindenmayer. It's notable as it is the
first comprehensive volume on the computer simulation of certain
patterns in nature found in plant development (L-systems).
This is the book that originally got me interested in L-Systems, and it was an
invaluable resource throughout this entire project. It goes into much greater
detail about the theory behind L-Systems, and it shows off some amazing
turtle-interpreted L-Systems while doing so! It is provided by one of the
co-authors of the book for free and in digital form at the below website. It is
a must read if you're interested in the subject!
TinyTurtle is a minimalist Turtle Graphics implementation using the
Tiny turtle is a little public domain project intended for teaching students basic
bunch of useful features, and I was able to easily extend it to do things like
saving and restoring states. It's small, it's simple, it's intuitive, I couldn't
ask for more.
Peter Collingridge wrote a lovely little tutorial about creating draggable SVGs.
It walks you through everything step-by-step with fun interactive examples. I
don't think I would have managed to make the turtle draggable without this tutorial.
Plus he has some articles about plant and other life simulation (something
l-systems are used for!) so I think that makes him pretty cool.