I have a bit of a puzzle I'm trying to answer. A K2 civ decides to celebrate Christmas, so they build a circuit of trillions of Christmas lights 1 LY in circumference. When they flip the on switch, what happens? Do the lights come turn on one after the other in response to the electrical field as it passes each light? Do they turn on all at once one year later when the field has made an entire loop around the circuit? Or do they need two years; one for the electrical field to make a full loop around the circuit, followed by another year for the information that the each light needs to turn on to travel down the circuit?