When I saw Woz demonstrating his "Nixie-Tube wrist watch", a behemoth that makes the Apple watch look like futuristic miniature tech, I decided it would be a cool custom watch face to develop for myself. However once it became clear Apple doesn’t want developers to create third party faces, I decided to simply make it anyway and put it on GitHub.
It was quite a challenge to build, in the end, since watchOS (especially watchOS 2, at the time) has very limited graphics capabilities. I had to render the watch face to an image buffer using CoreGraphics, output that to an image, and only then display on the screen.
Afterwards I modified it to render several “dummy” faces that are displayed in quick succession before the actual hour/minute faces in order to resemble the animations used by some of the other nixie watches out there.
It is a project I go over every once in a while and change some small things, and it certainly makes people curious when I show them my "exclusive" watch face.