These figures are much easier to read than normal approximately proportional Venn diagrams. First, the sets are always in the same positions on the plot and not moving around like on normal Venn diagrams. This feature makes it easy to compare the figures if several diagrams are drawn side-by-side. Second, the proportions are easier to read, because they all are depicted as similar shapes not as circles and cuts of circles as on ordinary Venn diagrams.
The function for drawing the figures is
bvenn
.