Sankey with circular links
A Sankey diagram with circular links shows the flow of patients through hospital departments, including circular paths where nodes at later stages return to earlier ones. Each link is rendered as a red or black path, and a dashed stroke animation indicates flow direction. The graphic uses the D3.js library, specifically the `d3.sankey` module, along with SVG rendering. The code animates the stroke-dashoffset of the circular paths to show the direction of movement.