This visualization presents an iris dataset scatter plot matrix, with off-diagonal cells showing colored scatter plots of trait pairs and diagonal cells displaying histograms of individual traits. The scatter plots use colored circles to distinguish the three iris species. Built with D3 v4, the code employs `d3.scaleLinear`, `d3.axisBottom`, `d3.axisLeft`, `d3.brush`, and `d3.histogram` to render the SVG-based matrix, with axes and frames styled via CSS.