When you eat Emmental, where do the holes go?

This is from Developing C/C++ Software in the OS/2 Environment, V. Mitra Gopaul. I hesitate to recommend this book now as it is somewhat out of date, and aimed at beginners. OK, so it is aimed at me.

"But the reality of our industry is that there are too many many programs out there that are unreadable, unmanageable and unmaintainable."

I know. I've co-written one of them!