This interactive bar chart demonstrates the difference between grouped and stacked layouts. Users can toggle between the two views using custom radio buttons. The visualization uses randomly generated test data with smooth bumps, displayed as an SVG with animated transitions. Built with D3 v6, the code employs `d3.stack()` for data preparation, `d3.scaleBand()` and `d3.scaleLinear()` for scales, and CSS-styled tooltips for mouseover interactions.