[lou1306]

But those are numerals. Made-up numerals, but still.

A friend of mine once prototyped a clock that would make a full walk along a loop in the RGB color space every 24 hours. That's closer to what I would call a "clock with no numerals".

[grvbck]

That's what I was thinking too. A clock without any culture-specific aspects could just rely on astronomy. The most objective form of that would just be a progress bar, from zenith to zenith. Perhaps with a marker half-way, and so on.