When you're working with graph theory or Discrete Event Systems, you're going to want to make graphs. Which are usually pretty visual things for analysis before you write an algorithm to deal with that for you, so then you want a way to draw your graph of arbitrary composition. Enter: GraphViz, a supremely useful tool for creating .jpg images of your graphs. The only caveat is making the conversions between how you encode your Graphs and how GraphViz draws them, but that's not a super tough one to figure out once you get your hands on GraphViz's api.
However: What if you want to do a fancy formal paper, and you need it in a slightly different format that lets you tweak things and, generally, jives well with an Academic Paper kind of setting? It turns out that when you look closely at a GraphViz .jpg, it gets kinda grainy, and when you print out that paper with its grainy images, it's just a bad time for professionalism.
So how about a different image file format that looks better? Like a(n) .svg? But then comes that second problem of being tweakable and just, in general, being usable with, say, LaTEX, the very useful software for writing Academic Papers. It has its own whole language for formatting, so instead of plopping a static image down inside there, why not translate it a bit?
I'm gonna put a read-more break here, because the point I'm leading to is that the file formatting is not pretty.