Custom function creating simple

As a simple first example of a Function procedure, we ll create a custom function to convert temperatures in degrees Fahrenheit to degrees Celsius. 

RP has progressed beyond the simple show and tell of a physical prototype to the ability to create functional prototypes for testing, customized products, and short production runs of standardized products. In addition, low-cost tooling can be built for fixtures, assembly tooling, and molds. 

---