This visualization presents the Old Faithful dataset as a 2D binned heatmap, with four panels showing combinations of the dataset’s numeric columns. A slider dynamically adjusts the maximum number of histogram bins for the x- and y-axes, while color intensity reflects the count of records per bin. Built with Vega-Lite and vega-embed, it uses a repeat operator to generate the grid and a `greens` color scheme for the heatmap. Data is loaded as CSV via d3.csv, and the visualization renders as SVG.