TVC once made a homemade Bardic lamp so he could communicate with his neighbour across the road using morse code instead of just phoning. As an extra part, TVC could convey what mood they were in at the time by changing the colour of the beam, so that green meant they were in a good mood, white neutral and red meant the mood was bad!
They had to stop after bringing down a light aircraft.
(oh no, I forget, not everyone knows what a bardic lamp is!).