Back in 2023 I built an online rock paper scissors game so my friends and I could settle arguments remotely. Open a room, send the link, best of three. I figured it was a weekend project. It's been running for about three years now, there's an iOS app, a Turkish sister site, and a matchmaking queue. And along the way this three-rule game kept teaching me lessons I thought only "real" systems taught. A few of them stuck with me. You can't leak what you never send The first de...