A floating bar: [start, end] rather than a magnitude from the
baseline. Chart.js draws gantt lanes, range bars and waterfall steps
this way.
A rectangle the treemap plugin laid out. It replaces the caller's
tree in dataset.data during chart.update(), so this union has to
admit it for the dataset to be read at all.
One weighted flow of a sankey dataset.
One region of a choropleth, or one bubble of a bubble map.
One node of a tree, dendrogram or force-directed graph.
Union of data value shapes found in Chart.js datasets. Covers native chart types and popular plugins (boxplot, financial, matrix).