Asemic:
Asemic writing is a wordless open semantic form of writing. The word asemic means “having no specific semantic content”. With the non-specificity of asemic writing there comes a vacuum of meaning which is left for the reader to fill in and interpret. All of this is similar to the way one would deduce meaning from an abstract work of art. Where asemic writing differs from abstract art is in the asemic author’s use of gestural constraint, and the retention of physical characteristics of writing such as lines and symbols. [Wikipedia]
Encountered in the letters column of NewScientist (19 October 2016).