Modern pandemics spread like this video you see below.
The rather random spread is actually much more direct that it appears at first view. What happens when you use a shortest path tree rather than a map?
The Atlantic covers the genesis of this reframing by theoretical physicist and professor of complex systems at Northwestern University, Dirk Brockmann.
"That made me think about, 'what is it that makes these different simulations be so much in agreement?'"Brockmann says. All of those other factors seemed to play little role. "My hypothesis was that much of it is driven by the structure of these mobility networks."[view whole blog post ]