A simple bar chart displays four data values as green rectangles, encoding each number through bar width while the y-axis positions them vertically. The visualization uses D3 v4 with an SVG rendering approach, employing `d3.scaleLinear` to map data values to pixel widths and `d3.axisBottom` to generate a horizontal axis. The `enter()` selection appends rectangles with fixed heights, while static data is passed directly to `d3.selectAll`. The chart demonstrates basic D3 data binding and axis creation without interaction or animation.