Mosaic plot (aka. mekko plot) is a normalized stacked column plot with variable bar width, which gives a direct visual image of complicated categorical data. It is very wildly used in mapping a market to spot large segments.
The graph above is a mosaic plot demonstrating the count and ratio of people that survived the Titanic tragedy.
Mosaic plot begins with categorical raw data. By using pivot table, we generate the statistical summary of the data by class against sex/age and plot it as a 100% stacked column plot.
Vertical ratio in the graph indicates the proportion of each class in total survived count, while horizontal ratio displays the proportion of different age/sex within the same class. Bar labels show the number of survivors in each category.
Axis and ticks are hidden for both X and Y axis and only labels are left.
Data Source: http://www.public.iastate.edu/~hofmann/data/titanic.html