[Fedetft] has an interesting project that combines two of those intriguing textbook references, he’s created a thermopile that lights an LED through an inverter whose oscillator is a tunnel diode.

Each Christmas period between 2016 and 2022, the city hosted the Tunnel of Light, a video tunnel of 57,000 LED lights which emulated the Aurora Borealis. Organisers said they believed the display ...