He didn't emphasize the number of lines written in that weekend, and that's important. The most productive programmers I've met don't talk about the number of lines, unless it is how many lines they eliminated. When they brag, it will be about finding a solution that is powerful and elegant, not how much they typed.

From the article: "And [Bret Taylor] rewrote the entire thing, making it 10 times as fast and a third of the size."