How to make a breadboard wristwatch

In the mid-70s I bought a Sinclair Black Watch kit with my hard-earned lawn-mowing money. It actually worked, at least some of the time. It burned through batteries. The most memorable part about it was the transparent purple plastic above the red LED display.

Inge's DIY watch reminds me of the Black Watch, but I like it even better. Build details are at Hackaday.