This is a true story that happened years ago, when I was working for a different employer than I do now.
I was on a team tasked with rewriting a math app to utilize a new framework. That new framework was codenamed Glass, and we followed that theme and gave the app itself the codename Crystal, or Crystal Math in full.
Not yet finished, the Crystal app couldn't be run by itself just yet, so we wrote a tool to run the parts of the app that were ready, and called that tool Lines.
My team was very productive, with everybody crackin' hard doing Lines of Crystal Math.
Or at least we did that until management found out, and insisted we'd find some less exciting codenames.