The neat thing about the lego example is it uses overlapping grids instead of overlapping circles.<p>Overlapping circles are familiar -- everyone made venn diagrams in primary school.<p>Problem is it&#x27;s notoriously subjective to use circles to map to some quantity.  Visualization blogs are rife with examples of people riffing on visualizations that confuse mapping circle radius vs. circle area to some quantity.<p>Using a grid (or legos) is nice because it eliminates that area-vs-radius ambiguity.