This example demonstrates a bug fix for SVG markers defined within `<defs>` elements, showing two variations of a "High" SPC icon with different performance states: improvement (blue) and concern (orange). The React components use d3’s `line` function to draw plot lines with circular markers applied via `marker-start`, `marker-mid`, and `marker-end` attributes. The fix ensures markers inherit the correct fill color from their parent definitions, rendering distinct colored endpoints for each performance state.