This example visualizes EEG signal data, letting users explore relationships between channels (e.g., F3 vs. F4) through scatterplots or line graphs. Buttons switch between beta, alpha, gamma, delta, and other datasets loaded from CSV files. The interface includes dropdown menus for selecting x- and y-axis columns and the chart type. Using D3 v6, the code builds SVG visualizations with animated circle transitions on scatterplots, and uses `scaleLinear`, `axisLeft`, `axisBottom`, and a `line` generator with `curveBasis`.