A scatterplot matrix displays hotel guest demographics and preferences, with one column per certified place. Each circle represents a guest, positioned by age range on the y-axis and jittered horizontally within their place's column. A mouseover on a bucket reveals a tooltip with totals, work and holiday counts, average age, and rate. Built with ECMA6 classes and d3-array v2, it uses a d3 scaleBand for age categories, d3.count and d3.sum for aggregations, and SVG transitions to animate circle placement. A dropdown filters by city, refreshing the data.