This visualization shows a 4x4 scatter plot matrix comparing all numeric fields of the iris dataset, with points colored by species using `d3.scaleOrdinal` and `schemeSet1`. Each cell pairs two variables, with axes drawn via `d3.axisLeft` and `d3.axisBottom`, and diagonal cells display variable titles. The code loads CSV data from a GitHub gist, parses it with `d3.csv`, calculates extents with `d3.extent`, and renders the matrix across the full window using multiple SVGs sized to a quarter of the viewport. It relies solely on D3 v6 in vanilla JavaScript.