Proportions
I saw a Calder painting which had a random pie chart in it, which made me think that would be cool if, XKCD style, it represented the proportions of colors in the picture. So...
I had to think for a second if adding the pie chart changed the proportion of colors in the whole image. That's what kept me from adding some Mondrian style black borders.
Play in GeoGebra. Now time to make the reverse...













