This is a great metaphor. I'm familiar with it, both stuff I've inherited and (unfortunately) stuff I've written myself. I do try to write a wall of comments

This is a great metaphor. I'm familiar with it, both stuff I've inherited and (unfortunately) stuff I've written myself. I do try to write a wall of comments for each hard-to-understand abstraction I'm introducing, including the rationale for the design, and why I haven't chosen the alternatives. This has been useful mostly for myself, as I'm still maintaining the same code after 12 years (or more, in some cases).