Patternodes is a tool for creating graphical patterns, animations, gradients, or illustrations based on repetitions. This is done by defining a sequence of steps, a recipe of sorts, that describes the pattern. Each pattern element or operation is represented by a little panel called a node, and the nodes are then linked by connections drawn between them. As the nodes can be freely combined and connected, this gives you a very flexible and powerful interface.
While this interface requires a different way of thinking, it also offers a lot of benefits compared to traditional Illustrator-type editors. Most importantly it enables you to use sliders to instantly change any aspect, like color, spacing, scaling, rotation or repetition count of any part of the pattern without having to undo/redo any steps. You can also specify animation value ranges for any of these parameters.
The resulting pattern tile is always shown in the bottom preview view, repeated and updating in real time with any changes, giving you instant feedback of what the end result will be. To make pattern creation easier Patternodes also includes a lot of nodes that automatically perform common tedious tasks like repeating elements at the tile edges to make the pattern seamless, or randomizing different aspects (like color, position, rotation, etc.) of the elements in a pattern to give it a little more life. Finally, when you're done you can simply copy the pattern tile into whatever illustration or graphics application you use, or export it either as vector graphics or a bitmap image file. Animations can be exported as GIF, QuickTime MOV or numbered PNG or JPG files