I was just re-reading these, and they're just as much fun as they were the first time.
Also, when I was re-reading R&R, Zoe's programming high in chapter 9 reminded me of Agatha Heterodyne in hyperfocus mode (I don't think I'd discovered Girl Genius the first time I read it.) Then I re-read Death and Liberty, and Zoe's actually called a madgirl! Hmm...
Author's Response: \'Madgirl\' came first; I wanted a casual slur that people in Zoë\'s world could plausibly throw at her, and it fitted all too well.
But taking the term more literally, Zoë\'s definitely a Spark. When she blows up the computer in \'The Invasion\', you can almost see where her speech bubbles gain wavy edges and go into MadFont.