This example displays water level measurements from two distinct wells as time-series line charts. A main chart shows the full dataset with circles marking individual observations, while a smaller brush chart below enables interactive range selection. The visualization relies on d3.csv for data loading, d3.nest to group measurements by well, and d3.line to generate the series paths. A d3.brushX instance with brush.move initializes the selection, while the `setBrushCoords` callback logs the selected time range coordinates to the console.