This example visualizes the distribution of miles per gallon (mpg) for 2012 vehicles using a box plot. It shows the minimum, first quartile, median, third quartile, and maximum values as horizontal lines and a shaded box, with numerical labels for each statistic. The chart is built with D3.js v4 and rendered as SVG, reading data from a CSV file. The code uses `d3.csv`, `d3.quantile`, and `d3.scaleLinear` to compute summary statistics and map the data to screen coordinates.