Wear OS usually does world time as a complication slot with a second zone in it. I wanted the mechanical thing instead: a fourth hand on a 24-hour scale, local hands left alone, the far zone set by the wearer.

Watch faces are written in Watch Face Format, which is XML with expressions and no code. Expressions can read the device clock and the device's own UTC offset, so UTC itself is easy: local hour times 60 minus the device offset, times 0.25 degrees per minute. That gives a fourth hand permanently on UTC.

What the format will not give you is the zone the user picked. A list configuration returns its option id as a string, and there is no arithmetic that turns a chosen option into an angle at runtime.

The way out was to stop treating the configuration as a menu. Placed in the scene it is a structural switch: it holds a set of alternatives and the system draws the one that is selected. So the option does not need to carry a number, the option can be the number. 28 copies of the same hand, each in a group with its own literal rotation, computed once while the file is generated. UTC+1 is a group at 15 degrees, UTC+5:30 at 82.5, UTC-11 at 195. The branches share one drawable, and the switch resolves before drawing, so 27 of them cost nothing per frame.

The whole story is written up here if you interested in more details and interactive prototype:

[https://timeflieswatchfaces.com/meridan-story](https://timeflieswatchfaces.com/meridan-story)

I built a caller GMT on Wear OS