This example displays four circles positioned along a horizontal axis, representing placeholder data points for auto sales by brand. The visualization uses D3 v5 to render the SVG elements, with each circle’s position and radius explicitly set via attributes. The code employs D3’s `select`, `selectAll`, and `join` API to bind the data array to the circles, while a fixed opacity value is applied. The circles lack fill colors, leaving them in their default black state, as no color data is assigned in the provided dataset.