So I take the hint, and that night, in my office, I start scouring the 80,496 lines of the Reiser4 source code. Eventually I stumble across a passage that starts at line 78,077. It's not part of the program itself — it's an annotation, a piece of non-executable text in plain English. It's there for the benefit of someone who has chosen to read this far into the code. The passage explains how memory structures are born, grow, and eventually die. It concludes: "Death is a complex process."