This plugin demonstrates flipping levers programatically.

== Issues ==

When flipping levers in unloaded areas of the world, only certain
effects in the same chunk containing the lever will take place:

- Only components (redstone, etc) in the same chunk as the switch are affected

- Only non-delayed reactions occur (so repeaters won't work and redstone lamps
  won't turn off)

To work around these limitations, you can create redstone circuits that touch
but do not affect the circuit with the switch that are activated when a player
comes near, e.g. with a pressure plate or minecart track plate.  For example:

    +---L---+-+       L = lever
    |   |   | |       m = lamp
  ttpttt\tttttpt      t = track
        t   |         \ = track switch
        p---+         p = track pressure plate
        t         - + | = redstone dust 
        t
        t
        t

If flipping the lever does not immediately affect the track switch (e.g.
because it's in a different chunk), running over any of the pressure
plates will cause Minecraft to recalculate the power on the wires coming
from the switch and your minecart will be routed properly.