Iconography experts:

Identification of True/False, Yes/No, Affirmative/Negative is a normal requirement... everywhere. In North America, common indicators for these are Red/Green or check/X symbols

There are known problems with these indicators: red/green is a common form of color blindness, and (most scarily) the symbols have the exact opposite meaning in different regions.

Is there a set of symbols that may be less well known, but still easily recognized, and more consistently understood internationally?