Fish eyes We often think of the same information at different levels or abstraction. Here's a simple example: Here's a close-up of a fish— we can see the scales, the texture of the fins, the faint reflection in the eye. Zoomed out a bit, the details are faded slightly. The surrounding ocean comes into view. Zooming out more, the fish is just a few splashes of color amongst a school of fish. Maps work in a similar way. Looking at a section of the National Zoo, we can see paths, buildings, and eve...