Collection. Within Block 7, the structural fifths engaged by the melody (A-E) and the harmony (B♭-F) are widely separated, far more so than in previous blocks. Harmonically, the music had been progressing slowly toward the flat side (D to G to C); Block 7 represents a leap in the same direction (B♭). At the same time, its melody (spanned by A-E), is a return to a structural fifth in play from the very beginning of the music.