squareplot: Create a squareplot alternative to a segmented barplot
Description
Create a squareplot as an alternative to a segmented barplot. Useful
when the viewer is interested in exact counts in the categories. A
squareplot is often used by the New York Times. A grid of squares
is presented with each color representing a different category. The
colors appear contiguously reading top to bottom, left to right. The
colors segment the graph as a segmented bargraph, but the squares
allow an interested reader to easily tally the counts.