margin structure, and neither do desert and steppe cultures. 
Today with jet and electricity, urban centralism and specialism 
reverse into decentralism and interplay of social functions in 
ever more nonspecialist forms.

     The wheel and the road are centralizers because they 
accelerate up to a point that ships cannot. But acceleration 
beyond a certain point, when it occurs by means of the 
automobile and the plane, creates decentralism in the midst of 
the older centralism. This is the origin of the urban chaos of our 
time. The wheel, pushed beyond a certain intensity of 
movement, no longer centralizes. All electric forms whatsoever 
have a decentralizing effect, cutting across the older 
mechanical patterns like a bagpipe in a symphony. It is too bad 
that Mr. Mumford has chosen the term “implosion” for the 
urban specialist explosion. “Implosion” belongs to the electronic