I built the original map 9 layers thick, just to make it stable. If you try to make a picture out of pennies on a table, one layer thick, they keep getting bumped around. If someone down the hall in the apartment building slammed their door, the pennies would move. So, 9 layers in the original. But there was a side-effect -- just staring at all those neatly-stacked pennies gave you a real sense of mass. You could bump the table, and they didn't move.
In 2012, when I started thinking about making the map again, I wanted to recapture that feeling. "People are going to look at this," I thought, "and know that something is there." It has the presence of a sculpture, but the picture of a painting.