This visualization compares annual birth statistics across four years by rendering each year as a hospital building, with the number of birth dots inside representing relative crowdedness. React manages the component state and container sizing via a custom `useContainerDimensions` hook, while D3 v7 handles SVG rendering and data joins through `d3.select` and `d3.csv`. The chart pulses with an interactive hover effect on hospital bodies, and the code explicitly generates synthetic multi-year data by applying variations to the loaded CSV totals from `data.csv`.