This visualization shows the social connections among dolphins as an adjacency matrix, where blue cells indicate a link between two individuals and white cells indicate no link. The data comes from a GitHub Gist and is processed by d3.text to parse the CSV-like input. Using D3 v7, the code builds a symmetric matrix for the undirected graph, then renders it as SVG rectangles with d3.selectAll and data joins. A tooltip is included but not actively bound to any user interaction in the visible code.