> At this point, Kitchen believes he knows the code well enough that he can hear it in music. Once, at a concert in Hong Kong, he was listening to a performance of Beethoven’s Piano Sonata No. 23 in F Minor, Op. 57—the “Appassionata.” He noticed an unstable chord that seemed especially ominous and unsettling—the kind of quiet but emotionally powerful moment that Beethoven often noted with one of his bespoke abbreviations.
> “I said, ‘I bet you that’s a two-line pianissimo,’” Kitchen recalled. After the performance, he checked. Sure enough: Scrawled below the disconcerting bass note troubling the otherwise serene chord, Beethoven had written a double-underlined pp. Two hundred years later, maybe Kitchen finally understood exactly what he’d meant.