Tonality and Centricity. Like so much of Stravinsky’s earlier music, his twelve-tone music is sometimes organized with reference to structural perfect fifths, which may be deployed either as chords (filled in various ways) or as melodic fourths, connected with passing notes. In this passage, the fourths E-B and F♯-C♯ are filled in as (0235) tetrachords and further elaborated with chromatic passing and neighbor notes. The structural fourths/fifths are related at T₂, just as in the second block of Petrushka. The larger T₂ relationship between the structural fourths/fifths is mirrored within each musical segment by the prevalent T₂-relations among the tones.