Creating a variable
Lets start by creating a variable called example. A variable is shorthand for numbers, text or code that you want to reuse.
Example equals a new protovis class file called pv. panel which defines an image area. Set the width and height at 150 pixels.
Notice the periods. These act like links in a chain. This is powerful because any information declared in the chain travels to the end, which is defined by a semicolon.
Remember that case and punctuation are important. If at some point your graphic stops working, check this first.