Yeah, I wouldn't be surprised if the tetris edit was in itself one of his tetris edits. I get into this mode sometimes, and while it's not always quality-producing, it is a fun, concept-pattern-matching exercise.
"Like my editor, you have probably already grasped that Tetris editing involves moving a chunk of story—a quote, a tip, an anecdote, even just a well-turned phrase—further and further down the length of the piece, trying it out in various spots in the narrative, until you finally find a place it fits. Just like in the game. If you get to the bottom of the story and haven’t really found a spot for it, it’s probably one of those darlings you need to slaughter." (From Double-Tongued Dictionary)