This example visualizes the distribution of sepal length across three iris species using a box plot with overlaid individual data points. Each species is represented by a vertical box showing the interquartile range, whiskers extending to the minimum and maximum values, and a line marking the median. Individual observations from the iris dataset are plotted as white circles with random jitter to reduce overlap. The visualization is rendered as an SVG using d3.v4, with summary statistics computed via `d3.nest` and `d3.quantile`, and scales and axes created using `d3.scaleBand`, `d3.scaleLinear`, and `d3.axisBottom` and `d3.axisLeft`.