a set of impressive maps that attempt to unravel any hidden organization of the ZIP code system used in the US.
the ZIPScribble map connects all the ZIP codes in ascending order. most of the empty, white zones separate states, while each little dense center seems to be a county.
the Travelling Presidential Candidate Map visualizes an attempt to calculate the shortest path through all ZIP codes, similar to the so-called Travelling Salesman Problem, using the Hilbert curve algorithm.
see also Ben Fry's interactive zipdecode.