This example visualizes the relationship between miles per gallon and vehicle weight for a dataset of cars, with each car represented as a semi-transparent red circle. The scatter plot uses linear scales for both axes, with axis gridlines and labels. The visualization is built with D3 v5, using `d3.csv` to load the data, `scaleLinear` to map values, and `axisLeft` and `axisBottom` to render the axes. Circle positions are set via the `cx` and `cy` attributes based on the scaled data values.