Rows 1 − 4: same as Fig. 10. Row 5: stellar density contours of galactic azimuth vs. radius. An attempt is made to match the waves of different multiplicities to the spiral features seen in the stellar density: pink vertical lines connect the most likely matches. Many waves cannot be seen in the stellar disc due to constructive/destructive interference. Row 6: incremental changes in angular momentum computed in 200 Myr spans, centered on the same times as the spectrograms above. The vertical green lines connect the likely waves/resonances and their effect on ΔL. The effect of the inner m = 2 spiral, as it sweeps its CR between the bar and the outer m = 2 wave, is shown by the green slanted line in the middle column. Resonant widths increase as the resonance curves (orange) flatten in the outer disc: clumps in ΔL are highlighted by the green shaded rectangles in the last three columns. Row 7: face-on differential stellar density contours for the same times.