Errors
A multitude of caveats.
- Any commands calling nodes must be read while TeX is still
processing the page the nodes are defined on. In other words don't
define the nodes on page 1 and connect them with commands that appear
at the end of the paper.
- Nodes mentioned in node connecting commands must exist or else
the job won't print.
- Make sure the dvips postscript output is sent to a postscript
printer. It is possible to send the dvi, but not the postscript,
output to another printer; the lines just won't appear, assuming the
printer ignores specials it doesn't know about.
