Picture of a disassembled Duracell 9v battery. Below the terminal assembly is a clear plastic case where you can see six sets of stacked rectangular terminals and fillings.
I got a Sylvania-branded strand of 50 “warm-white” LEDs (plus two loose spares) for USD 2.50 at the local grocery store, which I’m pretty sure is cheaper than buying a bag of the bare LEDs would run. They also come in other colours (blue, cool-white, bright red, multicolour)...
(screenshot of a rxvt window decorated with a fvwm theme. The title bar is rotated to the left and highlighted in red with white text, and reads ‘marada@kalutika:~’....