[amouat]

That's what I thought, but in the 2nd para:

> No Roman numerals. No Arabic numerals. No left-to-right reading direction. No assumed orientation. Something that works in a mirror, in zero gravity, in any language spoken on Earth or beyond it.

As other comments have pointed out, base 10 is a pretty big assumption though.

[vova_hn2]

Normal watch + "arc" remove the assumptions about orientation and direction.