This is fascinating, and from what I remember pretty accurate (although the opening, which is primarily green, is so evenly split it should be some kind of chequer-board). What’s mostly interesting is how little there is that’s pure red or pure green, which is how I remember it. Christmas, as they say in New Mexico, in answer to the State Question. It’s also why we were so unimpressed by anyone who thought they could tell us who wrote what, because when they cited things, they were mostly wrong.
Using a training set of texts by Pratchett and Gaiman, I used the R package Stylo to analyze Good Omens. (Specifically rolling nsc classification with 50 features and 5000 words per slice). The figure below shows my results. The words of the novel progress along the x axis. The pattern below the horizontal white line represents the signal from the author to whom the program attributed the majority of the authorship (Gaiman is in red and Pratchett is in green). The top, fainter pattern roughly shows how much signal there is from the other author. Together they add up to 100% in each section of the text.
I was amused to see a tiny sprinkling of me in Moving Pictures. Because there was a sprinkling of me in there. Terry would send me the book as he was writing it, and call to bounce ideas off me, and I’d cheerfully suggest lines and ideas. (There’s a sprinkling of me in Guards! Guards! and Moving Pictures, with a lot of me in Pyramids and Eric.)