It
It is a Mac OS X application for researchers in complex dynamical systems. It allows you to visualize complex functions under iteration, producing fractal images such as the famous Mandelbrot or Julia sets. It isn't limited to the Mandelbrot set, however. It lets you explore your own functions by writing code right inside the application. Your code is compiled on th
e fly and lets you create arbitrary graphics.
Images can be scaled and zoomed into. Parameters - declared in your code - can be manipulated through the application's interface. Once your image is ready, it can be exported to a number of formats: EPS, PNG, GIF, and PDF.
Image generation is fast because code is compiled, not interpreted. Furthermore, It can take advantage of multi-core machines to further accelerate calculations.
You can have a quick look at some of the possibilities of It in the screenshots section.
An introductory video and instructions are found on the manual page.
You can downloadIt from here. You may try It free of charge for as long as necessary. Continued use, however, requires a license.