Organum added what to gregorian chants

As no real independent second voice exists, this is a form of heterophony. In its earliest stages, organum involved two musical voices: a Gregorian chant melody, and the same melody transposed by a consonant interval, usually a perfect fifth or fourth.

Iwanna say its mayan. not a 100 % sure hope it : )

Yes because in graphic design you add elements of art into one piece and/or program. although, you place together graphic designs on a computer,  you still have to know about the principles of design which is included in art.