The TreeMap widget can be used as an extension of Proportion Charts : data is grouped in rectangles whose size and color can be bound to different data fields.
In a typical case, the size represents the importance, and the color represents the KPI itself.
This can be useful typically for showing the efficiency of something combined with the quantity.
Each rectangle is grouped by Equipment. The size of rectangles is bound to the Quantity produced, the color is bound to the energy Consumption.
In the above TreeMap, we can see that the Blender_001 has very bad energy efficiency, but represents only a small fraction of the total production.