SparkFun has a really interesting article about what a prototype means. The article includes a lot of interesting information on the development cycle that started SparkFun Electronics and the progression of the BlueSMiRF module.
Clearing out various boxes here at SparkFun Electronics, we come across piles of old prototypes. You may ask, what’s a prototype? It’s a design that we, the engineers, screwed up. May we bestow upon you a few rules to laying out a PCB.