Theorem Software Solutions Architect - Remote interview questions

I was asked to write some sample code (my answer is below). I normally don't like to do this, but I figured I could put it on my GitHub. I got an email from a recruiter a day or two later, which was to book time with an interviewer. That interview happened about a week later, and was a bunch of softball questions. The interviewer finished the interview by telling me she was putting me on to the next round. SIX WEEKS LATER... Time passes, I get another job, and forget about the interviewer's promise that I was on to the next round of interviews. I serve notice at my previous job, start the new job. Get my first pay. Then I get an email from Theorem telling me I wasn't selected for the next round of interviews. Cool.