The OpenProcessing site is a gallery of the amazing projects that have been made with Processing and p5js.
(Slightly confusingly, p5js is the modern Javascript version of Processing. Processing itself is java-based)
Not only is this site inspirational, you can also view the source code, and remix any project you like to develop your own version.
For Casey Reas, software is the most natural medium to work with. He uses code to express his thoughts—starting with a sketch, composing it in code, and witnessing the imagery that it ultimately creates. We visit his studio to see how he uses color to convey emotion and how his programming language Processing is closing the gap between software and object.