wold is a strange planet where you can grow sound-trees, and then play music on them!
Tired of static, impersonal and 2 dimensional interfaces for playing music like those boring, old, NORMAL instruments seem to have?Boooo
Start up wold. A tree will immediately start growing and making sound. You can grow more trees by holding down your finger anywhere on the planet, and let go to stop the tree from growing further. As they grow, the trees will ring out with descending pitches, and whichever one is the last to sound before you let go will be the sound of that tree. You can "play" a tree by tapping on the ground near its base, and it'll sing with that same pitch. Try turning the planet around by dragging with your fingers, growing new trees, and playing melodies on your new forests of sound!
(Careful, wold has some issues and will start to crap out if you get too crazy with the trees!)
wold's trees are generated using Lindenmayer systems, or L-systems. These are grammar-based fractal systems which are suited very well to simulating plant life. My trees are a modified version of one of the systems from this blog post.
L-systems renders typically implement some sort of 3D "turtle", inspired by LOGO. Althought I spent some time with a more turtle-like implementation for efficiency, my current version of L-system renderer directly manipulates the OpenGL matrix stack as it draws the trees.
You should simply be able to open the XCode project and immediately build and run the binary on an iPad. I'm not sure if it'll currently run on the simulator.