1. A method comprising steps of:propagating a message including an instruction, from a gateway to ancillary nodal devices in a flood network, wherein each of the ancillary nodal devices is within an equal number of transmissive steps of the gateway through the flood network such that the message is propagated with approximately equivalent delay to each of the ancillary nodal devices and substantially simultaneously received by all of the ancillary nodal devices;
substantially simultaneously transmitting the message from the ancillary nodal devices, wherein:
the transmitting includes transmitting the message from each respective one of the ancillary nodal devices to end nodal devices of respective group of the end nodal devices in the flood network coupled to or in communication with the respective one of the ancillary nodal devices, and
each of the end nodal devices of each respective group comprises a respective light source; and
upon receipt of the message from the ancillary nodal devices, substantially simultaneously executing the instruction, by each respective group of the end nodal devices of the flood network, wherein the executing comprises controlling a perceptible operation of the respective light source.