Now I can talk about it

Every so often I'll talk to someone who knows I work at Google. Invariably, the question will come up if they're technically savvy, "Is it true that that everyone gets 1 day a week to work on whatever they like?" I answer, "Yes." "What did you do with your time?" Unfortunately, I don't usually say much. But now I can point to this, and say, "I wrote the trading engine." (Actually, I rewrote it a couple of times before getting it right)