Visual debugging in TEX, Part 1: The story

This kind of fancy heading shows some dotted lines, rules and peculiar visual symbols. A closer observation shows that in fact it is some endoscopic view into what is often called TEX’s stomach. For those readers who have planned to skip the rest of this article, here is how the magic is done: \input supp-vis \showmakeup For those who want to take a closer look at all those kerns, skips and penalties, this article can be of some help. Although this kind of stuff often attracts the more hacking type of reader, the module described here can be of great help and provide a lot of fun to all TEX users, whatever macro package they use. [via]

http://www.tug.org/TUGboat/Articles/tb19-3/ha...