That's how a jury trial works. You need all 12 to agree, otherwise it is a hung jury and declared a mistrial. It is then up to the prosecutor to retry the case if they want to.
It isn't double jeopardy because the trial didn't come to a decision. If all 12 jury members agreed, one way or another, that is the end of it. At least for that/those counts.
If you are using the concepts and writing the code yourself, you're fine. If you are copying/pasting code from work to your personal project, you're commiting IP theft. I'd recommend never doing that. On the otherhand, if it is for a peraonal project that you will never give away or sell, no one will know. Id still recommend not doing it, but to each their own.