This example demonstrates an interactive bar chart with a hover tooltip. It shows a dataset of 20 numeric values represented as vertical bars, where hovering over a bar reveals its value in an HTML tooltip that follows the cursor. Clicking a bar triggers a sorting animation, alternating between ascending and descending order. The visualization uses D3.js v4.5.0 with `d3.scaleBand` for the x-axis, `d3.scaleLinear` for the y-axis, and SVG rect elements. The tooltip is positioned absolutely and updated on mouseover events.