The room-sized sculpture visually describes the vast differences in the wealth of the various "super neighborhoods" of Houston, TX. (A "super neighborhood" is a civic designation helping divide the wide-ranging and numerous parts of Houston TX in order to better provide city services through the census.)
Here is a small description from the Art League's website:
The City of Houston is known for its diversity. An underplayed aspect of this diversity is in the uneven distribution of wealth, which in its disparity, can be seen as one drives around the city. At times, these geographical shifts in income are subtle and hard to perceive; while in other instances the differences are severe, as in the case when low income neighborhoods abut million dollars high rises.
Here is a video with Brian Piana describing and explaining Wishing Well For Houston.
Houston is such a huge metropolis, with such a wide variety of people and incomes, that it is quite striking to see it all laid out, with the city freeway map serving as the horizontal and the median incomes serving as the vertical.