This example visualizes agricultural land distribution by age group using a Voronoi treemap, rendered as colored cells within a circular boundary. The layout uses the `d3.voronoiTreemap` plugin to partition hierarchical data from `globalEconomyByGDP.json`, with each cell sized by weight and labeled with age categories. The code sorts legend entries by computed mean productivity values, draws the treemap via SVG, and includes a button that exports the visualization to a PNG using `canvas-toBlob.js` and `FileSaver.js`.