This interactive visualization displays four layers of synthetic time-series data, switching between stacked and grouped bar layouts through animated transitions. Users toggle between modes via radio buttons, with sequenced transitions preserving object constancy as bars morph between the two arrangements. The example uses D3 v3 with SVG rendering, employing `d3.layout.stack` for stacking, ordinal and linear scales for positioning, and chained `transition()` calls with staggered delays to animate rectangle positions, widths, and heights. Colors derive from a linear scale spanning blue-gray tones, while data generation uses a bump function inspired by Lee Byron’s streamgraph test data.