I've been looking* for "the perfect visual timer" without success, so I'm thinking of 3d printing it, but I'm out of my depth

do any of you know a good pattern for a mechanical timer? or a mechanical visual timer?

I'm planning a form factor somewhere between the CogniTimer and the Secura (below) so I can
- carry it in my pocket
- set it one-handed
- stand it on my desk

#3DPrinting #Physibles #Maker #Pomodoro #PomodoroTechnique

*I use the Pomodoro technique to focus when I'm distracted