“They key difference between cities and companies, Lehrer tells us, is that despite what might often be the best of intentions, companies tend to silo knowledge by erecting “vertical hierarchies.” A CEO tells his employees what to work on. A CEO tells his employees to brainstorm on a given problem, a practice that Lehrer is quick to point out “very clearly doesn’t work.” In fact, these vertical hierarchies are exactly what stifles interaction, and holds a company back.”