What is Processing?
“Processing is a flexible software sketchbook and a language for learning how to code within the context of the visual arts” – from the Processing Website.
rect(10, 10, 50, 50);
This is a complete Processing program. It draws a square 50×50 pixels, 10×10 pixels from the top left corner of the screen.
The rest of Processing is designed to be similarly easy to understand. Install it and try out the many examples which come with the program.
The best place to see examples of Processing in action: