This scatter plot matrix displays pairwise relationships among four numeric Iris flower measurements, with points colored by species using a D3 ordinal scale. Each cell is an SVG chart rendered via `d3.axisLeft`, `d3.axisBottom`, and `d3.scaleLinear`, with diagonal cells labeling the corresponding dimension. The code loads Iris data from a GitHub Gist CSV, parses numeric fields, and iterates through all column combinations to generate a 4×4 grid of plots using `d3.csv` and `d3.select`.