Arduino and Processing

Arduino is a type of microcontroller. It is also the name of the programming language used for said microcontroller. Processing is a verb and a programming language for use along with Arduinos running an Arduino sketch. Confusing? Both Arduino and Processing programs are called sketches, and have a .pde suffix. Generally, we'll have an Arduino sketch running on the Arguing device, while a Processing sketch is running on the computer. Whew.

Exercise 2.4 from the Arduino Cookbook

I used two push-button switches with four prongs. It only worked when the prongs were attached diagonally.