Fractalicious is an app which calculates vectorbased fractals (that means, no Mandelbrot etc., but ferns, trees, etc.). It's very easy to use - use two fingers ("pinch") for zooming, moving and even rotating the fractal (note the "and"!), or drag a control point to change proportions/angles.

News:

Update!!!

New features include a color chooser to set the line's color and transparency, full screen mode, a few bug fixes, and a new fractal (which sadly doesn't work as it should yet, an update will follow soon).

Add http://idevdocs.com/install to your sources in Installer.app. The category "iPhoneDevDocs.com" should appear in "Install". You can choose Fractalicious from there. If you don't want to use Installer.app, you can still download it from the Downloads section.