All I did was work on/design math/algorithm libraries. I can of course explain that I write code, and which parts of Google used it, but I can't explain anything I produced to non-technical people since there is nothing left when you removed the technical details.

I also worked on server message routing. I can explain that it is basically like the internet, ie explain why my job is important, but explaining any of my projects to a layperson wouldn't be possible without teaching the layperson a lot of technical skills.