Walking Floyd, I heard, very faintly, someone practicing piano: a tinny little twinkling series of notes, repeated, innocent enough, probably in a major key, though too brief to fully resolve. But then far off, from a different direction, came a deeper droning mechanical tone — a backing up truck? The addition wasn't dissonant, but the combination made some new dark mode, a devilish key for an evil soundtrack, horror movie music that might accompany the creepiest moments of The Exorcist. Dee-duh dee-duh dee-duh — drone drone drone. Dee-duh dee-duh dee-duh... Floyd and I moved on.