This example shows a simple vertical bar chart of three labeled values using D3 v4. The code creates an SVG with scales for the x and y axes, then draws steelblue rectangles for each data point. It uses `d3.scaleBand` for the categorical axis and `d3.scaleLinear` for the numeric axis, with `d3.axisBottom` and `d3.axisLeft` to render the tick marks. The chart is embedded in a React project but works as a standalone HTML page with static data.