PErl Graphical Structures (PEGS)
are a nice technique for illustrating
data relationships, which I first saw in Hall and Schwartz's
Effective Perl -- The Shiny Ball Book : Table of Contents with chapter
They're great for enumerating the data types used, and if initialized,
variables and their values; PEGS are also good for depicting references.
Must have taken a lot of time with Framemaker.