My old flame

Singing candles are starting to appear in the shops. But how do they work?
The answer is in a patent filed by Wong Wai Pong of Hong Kong (GB 2 318 446).
The candle has a music synthesiser, tiny loudspeaker and battery buried in its
base. The battery is connected to the synthesiser through a pair of insulated
wires which run up the stem of the candle. As the wax burns, the insulation on
the wires melts and the wires make a circuit, which starts the music.