A network diagram maps related data-processing terms as colored nodes grouped into five hierarchical levels, with directed arrows showing learning dependencies between concepts. Built with D3 v5 and rendered as SVG, the visualization uses `d3.scaleOrdinal` to assign categorical colors and custom SVG markers for arrowheads. Links are drawn as simple lines with tooltips, while node positions are fixed by the dataset rather than a force simulation, presenting a static knowledge graph.