Name: Mengenlehre Set Theory Clock
Author: scheir.eu

Berlin's famous set-theory clock (Mengenlehreuhr) tells the time in rows of lamps.

- Top row: each lamp is 5 hours
- Second row: each lamp is 1 hour
- Third row: each lamp is 5 minutes (the red ones mark the quarters)
- Bottom row: each lamp is 1 minute
- The round lamp on top blinks every second

Add them up: 2 lamps in row 1, 3 in row 2, 8 in row 3 and 2 in row 4 make 13:42. The date, time and battery are shown too.

Works on 117 round Garmin watches (Connect IQ 3.1 and newer), from the Forerunner 255S and vívoactive 4 to the fēnix 8, epix, Venu and MARQ, on both MIP and AMOLED screens. On AMOLED watches it has its own dimmed always-on version that moves a few pixels every minute against burn-in. Seconds show for a few seconds after a wrist raise, to save battery.