<vex [number | nonumber][smaller | smallest]> text<\vex>
Default. Omits line numbers.
Puts a line number at the beginning of each line.
Displays the example using smaller fonts.This makes long lines fit within a narrower width.
Use this element when you need to display markup tags or other characters that could otherwise be interpreted as markup. Line breaks and spacing are preserved as they appear in the source file.
The smaller and smallest fonts enable wide examples to fit within the margins.