This example shows a dynamic multi-line chart where each line corresponds to a data column, toggled on and off via checkboxes. Using D3.js v6, it renders SVG paths for three series (`rt1`, `rt2`, `rt3`) against a linear mass scale, with a color scale based on `d3.schemeCategory10`. The checkboxes are generated from the data keys, and the `on("change")` handler updates line visibility by toggling the `display` attribute. The data is hardcoded in the script.