How can you create a box around an axis tick label in ggplot2?

Question

For several reasons, I am trying to duplicate the grotesque plot shown below. It violates many precepts of good data visualization so for training purposes my goal is to use

Answer 1

Slightly off-topic but this is a suggested quick-and-dirty workaround: export the graph as PNG (bitmapped) or SVG (vector-based) and manually add the black blocks with white text.