This example shows a time-series bar chart overlapped with a line graph, plotting five survey data points over a roughly 15-year span. Each bar represents a survey period’s start and end dates, with its height indicating the percentage value. The red line connects the middle date of each period to its value. The visualization uses React for rendering and d3.scaleTime, d3.scaleLinear, and d3.line to generate the SVG elements. Data comes from the local JSON file `timeperiodv2.json`.