Processing sketches for Arduino Cookbook, 3rd Edition. The Arduino sketches are here.
This is the official github repository for the Arduino Coobook, 3rd Edition by Michael Margolis, Brian Jepson, Nicholas Robert Weldin. You can find the book on O'Reilly, Amazon, and many other places.
If you are having any problems with the code here, feel free to open an issue, but you may also find the errata to be helpful.