But the twinkle effect until recently has been hard to describe. Typical flashing bulbs use a bimetallic strip. As the filament of the bulb heats up, the strip bends, opening the circuit.

This video explores heat conduction in brass and iron.

[Nathan Petersen] built a Hackable Open-Source Thermostat to smooth out temperature fluctuations caused by the large hysteresis of the bimetallic strip thermostat in his apartment. While it may ...