Beethoven's Secret Code

I like stories about discovering secret codes:

"Then, one evening in 2013, the violinist Nicholas Kitchen was in New Mexico coaching a quartet through Opus 132. Kitchen is a man of obsessions; one of them is playing from a composer’s original handwritten manuscripts, rather than printed music, so he had a facsimile edition on hand. The errant “ffmo” caught the eye of the quartet’s cellist. “What’s this?” she asked. 

As soon as Kitchen saw Beethoven’s mark, something in his brain shifted; later, he would tell people that it was as if someone had turned over a deck of cards to reveal the hidden faces behind the plain backs. Suddenly, he had a new obsession. Over the next several years, he would come to believe he had discovered Beethoven’s secret code."