I think that packet-switched pneumatic tubes could be interesting. Last time humanity tried pneumatic tubes we didn't really have packet switching, or electroni

I think that packet-switched pneumatic tubes could be interesting. Last time humanity tried pneumatic tubes we didn't really have packet switching, or electronics that could wirelessly read labels off of fast moving packages. I think a new pneumatic tube network with a simpler network topology (ring networks?) could do very well in urban cores.