Software » Processing
"Processing is an open source programming language and environment for people who want to program images, animation, and interactions.... It was created to teach fundamentals of computer programming within a visual context and to serve as a software sketchbook and professional production tool. "
Learn more and download Processing @ the official Processing site.
My Processing sketches:Square Flower Rotations Poi Bounce
These sketches can use a decent amount of processing power. They might perform poorly on older computers.
My video page has some videos I made with Processing.