Holden McCormick, age 14, used topography, as his inspiration for this skull. I had to look more into topography to understand the lines in the skull. Topography is part of map making. It deals with the 3D space...the elevations of mountains, hills, valleys and everything in between. I live in an area with lots of hills, valleys and curves. Occasionally, I'll see a couple surveyors along a steep curvy stretch of road, attempting to figure out the lay of the land.