The first LED points forwards and the second diode is reversed ... and for an added treat check out his 2011 Advent Calendar of Circuits.

By combining 49 of them he’s put together a soda bicarb diode steering circuit for a 7-segment display capable of showing the digits 0 to 9. He takes the idea for his diode from electrolytic ...

The semiconductor light-emitting diode, or LED, is a key component of today's ... is used as the light source connected directly to a circuit of modulated current.” Unknown and uncelebrated ...