In this official government map of the Washington, DC region, you
see the classic design of the region: metropolitan centers surrounded
by concentric transportation rings. There are several theories on how
this design came about:
It reflects the common local tendency to travel in circles.
It is a diversion to enemy bombers, centering on where the
politicians gather (airport bars) and away from more critical
areas (where the tobacco price support checks are written).
It is a Zen lesson in life, showing how a rock thrown into a
pool will create ripples, but the ripples will slowly fade away to
nothing.
It was an accident: someone set several coffee cups on a map
during a break, and these were misinterpreted as construction
orders.