Yeah, I’ve spent a lot of time on the $10 bill’s layout. The designers did line up the landmarks so that their centers fall on the golden ratio points, which gives the composition a natural balance. As for the serial numbers, they’re basically a stream of random digits and letters generated by the Bureau of Engraving and Printing. I ran a quick scan for Fibonacci or any repeating subsequence and got nothing that held up under statistical testing. So unless someone sneaks in a secret code with a very good reason, it’s just a random string. The real pattern work is in the art, not the serial.