This example displays a weekday hourly heatmap for three days and 24 time slots, with each cell colored by its value on a blues sequential scale derived from a quantile color scale. It loads tabular data from a local TSV file using `d3.tsv`, renders SVG rectangles with rounded corners, and animates color transitions over one second using `transition.duration`. A legend at the bottom shows the quantile thresholds. The code uses D3 v3 selection methods, data joins, and scale functions, with categories labeled along the axes.